Exploring the Risks of the Large Hadron Collider

[ZapperZ]

Did you read my previous post?

I defined a black hole as such:
A point particle which can classically have an event horizon ("classically", solely because it is not clear yet without a full quantum theory of gravity how to answer this quantum-mechanically).

If you do not like that definition, then please do give me your definition.

Apply my suggested definition to the currently observed particles in the standard model and you will find that none have an event horizon due to their charge or angular momentum being too large. The Higgs boson, if observed, would be the only particle in the standard model which would have enough mass, and small enough charge (zero) and angular momentum (zero) to classically have an event horizon.


I'm sorry if I am not clear, but since people's questions seem already answered to me, I am also not sure what the confusion is, so am unsure how to fix it. Please, please, if you disagree can you provide your own definition of a black hole so that discussion can move forward.

How are you able to define these thing to whatever you please? Have you published this definition, or are there any papers out there that used this definition?

Zz.

 

[JustinLevy]

Three counter-arguments. Pick your favorite:

(1) I can take a black hole of mass $$M_1$$ and turn it into a black hole of mass $$M_2$$ by firing a photon of the correct energy at it. I believe that energy is $$E = \frac{M^2_2 - M^2_1}{2M_1}$$.

(2) While a quantum mechanical potential gives rise to discrete states, the energies of the discrete states are functions of continuous parameters of the potential. So while the energy of any given example is discrete, the range of possible examples is continuous.

For example, the energy of a simple harmonic oscillator is quantized in units of its natural frequency, but I can have a SHO with any frequency I like.

(3) The quantization of energy states comes from matching wavefunctions of the internal structure of the system. Black holes don't have an internal structure.

What the heck?
As I said, the discrete spectrum of black holes "appears to be required by quantum mechanics, as both LQG and String Theory, and most if not all other candidate [quantum gravity] theories, predict this."

This isn't even a central aspect to my question. But you focussed on it, and if you don't feel the fact that current quantum gravity theories predict such things is enough for you to maintain a healthy sense of "plausible" here, then I don't know what I could possibly say to help you. But I thought you seriously were asking, so I tried to give a simple over generalization to give you a picture ... and you ignore everything but this, and jump on me for it. Seriously, what the heck?

This is usually a very friendly forum, but I'm having trouble containing my frustration this time (as is probably obvious).

How are you able to define these thing to whatever you please? Have you published this definition, or are there any papers out there that used this definition?

Zz.

Okay, that's it. What is going on here?

I've asked many many times for a definition and no one will provide one, but people seem more than glad to berate me on my attempts. My original post was titled "What is definition of micro-blackhole?"

I asked this because I wanted to _learn_.
I gave what I felt was a reasonable starting definition to aid discussion. But all I keep getting is people berating me, seemingly enjoying the fact that I don't know what the correct definition is ... and leaving this to continue forever because while I'm told I'm wrong, no one will supply their own definition that I should be using. This is no way to help me learn.

So please, PLEASE, if you don't like my suggested definition, tell me what I SHOULD be using.


Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?


;------------
I might as well reply to some of Vanadium's statements.

(1) This is too classical. The quantum black hole could quite well absorb some light and scatter the rest. We'd need a theory of quantum gravity to predict what would actually happen, and the point is that major theories of quantum gravity DO predict discrete energy levels of a black hole.

(2) While you can create SHO with varying potentials (effectively change the 'spring constant' k), for a black hole in vacuum there is nothing to adjust. The gravitational coupling is what it is.

(3) In quantum theories of gravity, black holes DO have internal structure, and this is how they are able to match the Hawking entropy <--> microstates.

Finally, if you sweep all that aside, the Higgs still can't be a black hole because the couplings are all wrong. For example, a black hole certainly interacts with photons (hence the name "black") but the Higgs does not.

A neutral black hole will couple with the photon due solely to gravitational couplings. Regardless of whether or not you consider the Higgs a black hole, it too will couple with the photon gravitationally. The standard model can't tell us these gravitational couplings, but that does not make such couplings zero. Indeed, for GR to be the classical limit, any massive particle needs to gravitationally couple to the photon.

 

[Evales]

So if collisions with this level of energy are created all the time and we are searching for the "God" particle... does this mean it is possible that particles that give things the property "mass" are produced all the time in our atmosphere?

 

[JustinLevy]

Yes, if the Higgs exists, high energy collisions in the upper atmosphere can produce them. But their lifetime is too short for us to be able to detect them this way. Even with the amazing detectors in the LHC, centered righ around the collision, it will be quite a feat for experimentalists to get the hang of removing all that background of other collision processes.

 

[Orion1]

Reissner-Nordström charged black hole...


Do charged quantum black holes obey the Reissner-Nordström metric?

The Schwarzschild radius r_s of an (4+n)-dimensional charged black hole:
$$r_s = \frac{r_p}{\sqrt{\pi}} \left[ \frac{E_{BH}}{E_p} \left( \frac{8 \Gamma\left(\frac{n+3}{2} \right)}{n+2} \right) \right] ^{\frac{1}{n+1}}$$

Charge radius:
$$r_{Q}^{2} = \frac{Q^{2}G}{4\pi\epsilon_{0} c^{4}}$$

$$r_b \pm = \frac{r_{s} \pm \sqrt{r_{s}^2 - 4r_{Q}^2}}{2}$$

Charged black holes dual horizon radii quadratic equation solution:
$$\boxed{ r_b \pm = \frac{1}{2} \left( r_{s} \pm \sqrt{r_{s}^2 - 4 \left[ \frac{Q^{2} G}{4 \pi \epsilon_{0} c^{4}} \right] } \right) }$$

The Reissner-Nordström dual horizon radii of an (4+n)-dimensional charged black hole:
$$\boxed{r_b \pm = \frac{1}{2} \left( \frac{r_p}{\sqrt{\pi}} \left[ \frac{E_{BH}}{E_p} \left( \frac{8 \Gamma\left(\frac{n+3}{2} \right)}{n+2} \right) \right] ^{\frac{1}{n+1}} \pm \sqrt{\frac{r_p}{\sqrt{\pi}} \left[ \frac{E_{BH}}{E_p} \left( \frac{8 \Gamma\left(\frac{n+3}{2} \right)}{n+2} \right) \right] ^{\frac{2}{n+1}} - 4 \left[ \frac{Q^{2} G}{4 \pi \epsilon_{0} c^{4}} \right] } \right) }$$

Strong Gravitation: (1 Tev)
(Quantum BH strong nuclear reaction with a proton)
$$\boxed{t_p = \frac{4 E_b^2}{3} \sqrt{\frac{m_p r_p^7}{2 (\hbar c)^5}}}$$

The lower limit cross section for the Higgs boson at 160 Gev is:
$$\sigma = 33.22 \cdot 10^{-43} \; \text{m}^2$$

The upper limit cross section for a quantum black hole at 10 extra dimensions and 14 Tev:
$$\sigma = 5 \cdot 10^{-76} \; \text{m}^2 \; \; \; n = 10$$

The Higgs boson is definitely not a quantum black hole.

Reference:
http://www.youtube.com/watch?v=kVsZdgz5oFM"
http://en.wikipedia.org/wiki/Reissner-Nordstr%C3%B6m_metric"
https://www.physicsforums.com/showpost.php?p=1871641&postcount=368"
http://www.wissensnavigator.ch/documents/OTTOROESSLERMINIBLACKHOLE.pdf"
http://en.wikipedia.org/wiki/Higgs_boson"
http://en.wikipedia.org/wiki/1_E-28_m%C2%B2"
http://www-cdf.fnal.gov/physics/new/hdg/results/combcdf_080801/#Xsec"

Leave, leave Geneva every last one of you,
Saturn will be converted from gold to iron,
RAYPOZ will exterminate all who oppose him,
Before the coming the sky will show signs.

 

[tiny-tim]

Hi JustinLevy!

Please reread my post. I did refer to an event horizon …

Yes, but you didn't define it …

This starts to get into the definition of a black hole. What I'm using as the definition is just a point particle which can classically have an event horizon ("classically", solely because it is not clear yet without a full quantum theory of gravity how to answer this quantum-mechanically). I aksed how people here are defining it, so please do feel free to share your working definition if you disagree.

Using that definition, and assuming (as the standard model does) that the lightest mass particles with zero for all quantum numbers is the Higgs, then yes... it seems like the Higgs would be the smallest allowed black hole.

you defined a black hole.

(btw, you have a bad habit of quoting yourself without giving the reference. )

What I'm using as the definition is just a point particle which can classically have an event horizon ("classically", solely because it is not clear yet without a full quantum theory of gravity how to answer this quantum-mechanically). I aksed how people here are defining it, so please do feel free to share your working definition if you disagree.

Using that definition, and assuming (as the standard model does) that the lightest mass particles with zero for all quantum numbers is the Higgs, then yes... it seems like the Higgs would be the smallest allowed black hole.

… and that is because the Higgs as a fundamental point particle would have an event horizon (while none of the other particles in the standard model will).

So if your definition of a BH is also that is it a mass which would have an event horizon ... then you too are also calling the Higgs a black hole.

erm … no I'm not! …

I'm not calling the Higgs something "which would have an event horizon" (which, of course, is why I was keen to define an event horizon )

I'm calling the Higgs "an ordinary electroweak-theory particle" …

I don't understand what there is in electroweak-theory that makes you say that the Higgs must have an event horizon.

Which equations do you get this event horizon from? ​

 

[ZapperZ]

Okay, that's it. What is going on here?

I've asked many many times for a definition and no one will provide one, but people seem more than glad to berate me on my attempts. My original post was titled "What is definition of micro-blackhole?"

I asked this because I wanted to _learn_.
I gave what I felt was a reasonable starting definition to aid discussion. But all I keep getting is people berating me, seemingly enjoying the fact that I don't know what the correct definition is ... and leaving this to continue forever because while I'm told I'm wrong, no one will supply their own definition that I should be using. This is no way to help me learn.

So please, PLEASE, if you don't like my suggested definition, tell me what I SHOULD be using.

Did you even read the Peskin review?

Zz.

 

[tiny-tim]

micro-black-hole

My original post was titled "What is definition of micro-blackhole?"

You've given no reference to that post, and I've no intention of ploughing my way through 24 pages to find it :rofl: :rofl:

But let's have a go at answering the title rather than the post itself …

Our sages tell us that one evening Lucky Eddie and Hagar the Horrible were sitting round a table when Hagar asked "Eddie, what's it like being thin?", and Eddie thought hard and then replied "Much the same as being fat, I suppose … only thinner! "

Fom this we learn that we must define a micro-black-hole to be just the same as an ordinary black hole …

only very much smaller! ​

 

[Orion1]

Correction: source code correction (30 min. time limit)

The Reissner-Nordström dual horizon radii of an (4+n)-dimensional charged black hole:
$$\boxed{r_b \pm = \frac{1}{2} \left( \frac{r_p}{\sqrt{\pi}} \left[ \frac{E_{BH}}{E_p} \left( \frac{8 \Gamma\left(\frac{n+3}{2} \right)}{n+2} \right) \right] ^{\frac{1}{n+1}} \pm \sqrt{\frac{r_p^2}{\pi} \left[ \frac{E_{BH}}{E_p} \left( \frac{8 \Gamma\left(\frac{n+3}{2} \right)}{n+2} \right) \right] ^{\frac{2}{n+1}} - 4 \left[ \frac{Q^{2} G}{4 \pi \epsilon_{0} c^{4}} \right]} \right)}$$

 

[Almanzo]

I think the fundamental error you make is that you do this in Euclidean space. You integrate with an Euclidean space element and you calculate distances using an Euclidean metric. But near the Schwarzschild radius, the metric is far from Euclidean. So your energy calculations from the E-field and so on are all off.

Anyone reading this: I tried to multi-quote, but it doesn't seem to work, so I did a normal quote. Vanesch refers to a post of mine about a calculation of the minimum mass for a charged black hole.

Vanesch: You are right. Using a normal Euclidean volume element for an integration in the highly warped vicinity of a black hole invalidates the result.

But, strangely, the Wikipedia article you refer to, seems to suggest that the result is "right" by coincidence. If I understand rightly what it says about the metric, I should not use dV = dr * rdtheta * r*sin(theta)dphi, but divide this by the square root of 1 - r/r_s + r²/r_Q². Here r_s is the Schwarzschild Radius itself, and r_Q² is equal to GQ²/4*pi*epsilon*c⁴. These two terms seem to cancel each other near the Schwarzschild radius of a hole with the radius which I originally calculated.

However, there might now be multiple solutions, so I will try to redo the entire calculation and post the result around next weekend. (By the way, I cannot use greek letters here; if I try to import greek letters by pasting them from an ASCII file, they get changed into other symbols, which is why I write them out as theta, phi, pi and epsilon.)

Even if the result changes by several orders of magnitude, would it not still be true that a 10^-50 meter black hole is just too small to acquire an electron charge without violating energy conservation? That would be very nice; such holes would be unable to grow except by encountering each other.

 

[ZapperZ]

I think the fundamental error you make is that you do this in Euclidean space. You integrate with an Euclidean space element and you calculate distances using an Euclidean metric. But near the Schwarzschild radius, the metric is far from Euclidean. So your energy calculations from the E-field and so on are all off.

You can of course start a discussion on a scientific topic concerning black holes ; however, we try to group all the LHC-will-create-a-black-hole and will it or not destroy the Earth stuff in one single thread (this one). The reason for this is that we wanted to avoid a "pollution" of the particle physics forum, with the same questions, fears, and answers discussed over and over.

If you want to discuss a specific scientific topic, unrelated to what will happen in the LHC, you are of course free to do so in a separate thread.

However, no, the Higgs (at least, the standard Higgs in the standard model) is not a BH: a BH is a concept from GR, while in the standard model, there isn't even any gravity present. Now, as to whether a kind of elementary black hole could play the role of the Higgs in one or other quantum gravity theory, I'm out of my depth.

Anyone reading this: I tried to multi-quote, but it doesn't seem to work, so I did a normal quote. Vanesch refers to a post of mine about a calculation of the minimum mass for a charged black hole.

It's working for me. Are you sure you did it correctly?

Zz.

 

[JustinLevy]

I'm not calling the Higgs something "which would have an event horizon" (which, of course, is why I was keen to define an event horizon )

I'm calling the Higgs "an ordinary electroweak-theory particle" …

I don't understand what there is in electroweak-theory that makes you say that the Higgs must have an event horizon.

Which equations do you get this event horizon from? ​

You have defined an event horizon, but given nothing to determine whether a particle has one or not. So you have not answered the question at all.

Which equations do I use to determine if there could be an event horizon? I already stated: GR.
GR provides that a point particle with a finite mass and zero spin and charge will have an event horizon.

Furthermore, the Higgs has zero of every quantum number. Thus is has the same quantum numbers as a neutral black hole with no angular momentum. Let's say hypothetically there is a micro-blackhole with the same mass as the Higgs. How would you define a black hole that would distinguish between these two things that have the same quantum numbers? Could an experiment even distinguish them in principle if they have the same quantum numbers?

The question here is:
Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?

I would be interested in hearing your answer.

Did you even read the Peskin review?

Zz.

Was I "even" presented with the Peskin review? No.
I appreciate any help you can provide me, I really do, but please stop talking down to me.

If you provide a link I will gladly read up on sources.


Orion1,
I appreciate seeing some calculations, but it doesn't answer the question: What is the definition of a black hole?

Worded more directly: Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?

If the cross-sections are greater or less than your calculations, would that automatically disqualify it as a black hole to you? (So if your extrapolations down to the Planck scale are wrong, then you would never consider anything to be a black hole?)

 

[ZapperZ]

Was I "even" presented with the Peskin review? No.
I appreciate any help you can provide me, I really do, but please stop talking down to me.

If you provide a link I will gladly read up on sources.

Message #165 in this thread, and was mentioned several times.

https://www.physicsforums.com/showpost.php?p=1865737&postcount=165

Zz.

 

[JustinLevy]

Okay, I read that now.
The closest I can find to a definition of a black hole is:
"They imagined that the black holes would glow with a temperature of about 1 TeV/kB, emit large numbers of quarks, leptons, and bosons through Hawking radiation [8], and evaporate in 10-26 s. This process would produce unique and unmistakable events detectable by the LHC experiments."

It seems that if it decays thermally via Hawking radiation, then they consider it a black hole. Otherwise not.

Is that a fair characterization of their working definition?

 

[ZapperZ]

At the risk of sounding "condescending", did you read the actual paper that he was reviewing? The Giddings and Mangano paper is available for free.

Zz.

 

[Orion1]

What is the definition of a black hole?

A black hole is a theoretical region of space in which the gravitational field is so powerful that nothing, not even electromagnetic radiation, can escape its pull after having fallen past its event horizon and evaporates via Hawking radiation.

What properties would it have to have before you'd consider it a black hole?

It would require a cross section that is less than or equal to:
$$\sigma = 5 \cdot 10^{-76} \; \text{m}^2 \; \; \; n = 10$$

...and evaporate via Hawking radiation:
$$T_b = \frac{\hbar c^3}{8 \pi G M k_b}$$

If the cross-sections are greater or less than your calculations, would that automatically disqualify it as a black hole to you?

If the cross-sections are greater than my calculations, then it is probably a Higgs boson.
If the cross-sections are less than my calculations, then it is a probably a quantum black hole.

if your extrapolations down to the Planck scale are wrong, then you would never consider anything to be a black hole?

If my extrapolations down to the Planck scale are wrong, then this theory is wrong.

Reference:
http://en.wikipedia.org/wiki/Black_hole"
https://www.physicsforums.com/showpost.php?p=1875406&postcount=398"
https://www.physicsforums.com/showpost.php?p=1875488&postcount=402"

 

[phyzzy]

I was pondering over the stability issue of the forthcoming LHC experiment and it made me think about the concept of review committees. The biological sciences have ethics committees, and other external bodies, which try to regulate cellular-based experiments from inducing harm from whatever perspective you look from. What about experiments of this nature? Sure there have been numerous reviews done by physicists i.e. Giddings & Mangano (2008). But what external bodies did the physics community have to convince to allow an experiment of this scale the go-ahead? Or are there any such external bodies? Or are the physicists at CERN self governed/administrated thereby allowing them to perform whatever collision experiments they so choose to devise?

phyzzy

 

[Orion1]

Astrophysical implications of hypothetical stable TeV-scale black holes - Giddings and Mangano.

Reference:
http://lsag.web.cern.ch/lsag/CERN-PH-TH_2008-025.pdf"

 

[JustinLevy]

At the risk of sounding "condescending", did you read the actual paper that he was reviewing? The Giddings and Mangano paper is available for free.

Zz.

The paper makes no effort to define a black hole or how a black hole would be distinguished from other particles (since that is not what the paper is focussed on). And they focus on an incredibly hypothetical situation in which the black holes are stable for some reason. So if you are going to include those, you can't even use Hawking radiation to detect them ... it sounds like they could just show up as missing energy in the detector.

So no, that does not help me. If we are to include those, it makes it even more difficult to explain how we know if the collider succeeds in making a black hole. I'd prefer to just ignore that extremely hypothetical situation, as it was introduced merely as a 'worse case scenario' focussing on safety, rather than what is expected logically from all the physics we currently know.


Can you please (pretty please?) just answer the question to the best of your ability:

Since the Higgs has zero quantum number for everything, doesn't this have the same quantum numbers as a neutral black hole with no angular momentum?

Let's say hypothetically there is a micro-blackhole with the same mass as the Higgs. How would you define a black hole that would distinguish between these two things that have the same quantum numbers? Could an experiment even distinguish them in principle if they have the same quantum numbers?

Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?



Orion1 suggests we would distinguish them based on cross section ... but I am confused here. If a Higgs and a black hole could have the same quantum numbers, then how could their cross sections differ at the same energy? Unless I am misreading your numbers, you are not quoting the cross sections at the same energy.

 

[Orion1]

Since the Higgs has zero quantum number for everything, doesn't this have the same quantum numbers as a neutral black hole with no angular momentum?

Affirmative.

In scattering, a differential cross section is defined by the probability to observe a scattered particle in a given quantum state per solid angle unit, such as within a given cone of observation.

how could their cross sections differ at the same energy?

Cross sections are different, for different particles at the same energy because of the physical differences in a scattered particle in a given quantum state per solid angle. (ref. 1)

How would you define a black hole that would distinguish between these two things that have the same quantum numbers?

By the differences in their cross sections and their radiation types and decay particles quantum numbers.

Could an experiment even distinguish them in principle if they have the same quantum numbers?

Affirmative, by the differences in their cross sections and their radiation types and decay particles quantum numbers.

you are not quoting the cross sections at the same energy.

The lower limit cross section for the Higgs boson at 160 Gev:
$$\sigma = 33.22 \cdot 10^{-43} \; \; \text{m}^2$$

The upper limit cross section for a quantum black hole at 10 extra dimensions and 160 Gev:
$$\sigma = 2.214 \cdot 10^{-76} \; \; \text{m}^2 \; \; \; n = 10$$

I have not studied any theory that suggests quantum black hole generation at this low energy scale.

Reference:
http://en.wikipedia.org/wiki/Cross_section_(physics)"

 

[tiny-tim]

micro-black-hole

Which equations do I use to determine if there could be an event horizon? I already stated: GR.
GR provides that a point particle with a finite mass and zero spin and charge will have an event horizon.

But GR also provides that a point particle with a finite mass and non-zero spin (provided the spin is not too large) and non-zero charge will also have an event horizon (and an ergosphere).

So quarks and electrons should, on the same argument, be regarded as having event horizons, and as being micro-black-holes, just as much as the Higgs.

What is special about the Higgs?

However, I don't accept that "point particles" exist … the Higgs, like any other "particle" is a wave with inaccurately-defined position.​

Unless the mass of the Higgs is large enough to make its Schwarzschild radius larger than the Planck length, I don't see how it can be dense enough to have an event horizon.

Surely the Higgs can't possibly be a point, and can't even be dense enough enough to fit inside its Schwarzschild radius? ​

The question here is:
Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?

I would be interested in hearing your answer.

I've no idea …

but so long as it doesn't swallow anything else up …

in other words, so long as it keeps to itself, and collides and decays in the usual way …

… that is, so long as it behaves just like any other particle …

why does it matter?

 

[vanesch]

Can you please (pretty please?) just answer the question to the best of your ability:

Since the Higgs has zero quantum number for everything, doesn't this have the same quantum numbers as a neutral black hole with no angular momentum?

I think that the answer to this one is dependent on the quantum gravity theory you consider. After all, the quantum numbers you talk about are the quantum numbers within the standard model, which doesn't say a word about gravity, and GR doesn't have any quantum numbers as it isn't a quantum theory. At most, we can find a quantum-classical correspondence of some quantum numbers, like charge or angular momentum. Who says that a "quantum black hole" doesn't have a "gravity quantum number" equal to, say, 1, while all particles in the standard model have gravity quantum number 0 ? There's no way to tell if you have no theory behind it. It is as if you were saying that quarks and leptons must be the same, simply because you ignore the color force, and hence the color quantum number. It is not because in electroweak theory, leptons have no color quantum number, and the electroweak part of quarks also have no color quantum number (simply because you ignore it), that this makes that quarks and leptons are the same. So there may be gravity quantum numbers out there, which distinguish the Higgs from BH, but without a quantum theory of gravity, how are we going to even define the quantum numbers of a BH ?

Let's say hypothetically there is a micro-blackhole with the same mass as the Higgs. How would you define a black hole that would distinguish between these two things that have the same quantum numbers? Could an experiment even distinguish them in principle if they have the same quantum numbers?

As somebody else pointed out, the interactions with say photons are different between BH and Higgs - or at least, with a mini-classical BH and Higgs.

Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?

We reach here the fundamentals of science: you need to have a theory that makes predictions, and then verify observations with those predictions. If you haven't gotten any theory, then you cannot verify it. At its basis, an experiment such as the LHC just gathers a huge amount of data which describe tracks of charges in big detectors and it is up to the experimentalists and theorists to sit together and find out whether those data correspond or contradict predictions of theories.

There is no "black hole" or even "higgs" detector in ATLAS or CMS. There's just charged particle track detectors. Theory predicts a certain statistical behaviour of the events, and if you find back those statistics, then that's a kind of confirmation of said theory.

Remember, the neutrino has remained undetected for decades, even though it was massively produced in many interactions. If there are somehow some stable BH produced which don't interact with matter, it will almost be impossible to detect them, or even to find out that they were produced, given the superposition of events in LHC (so very difficult momentum balance).

 

[Vanadium 50]

There is no "black hole" or even "higgs" detector in ATLAS or CMS. There's just charged particle track detectors. Theory predicts a certain statistical behaviour of the events, and if you find back those statistics, then that's a kind of confirmation of said theory.

Remember, the neutrino has remained undetected for decades, even though it was massively produced in many interactions. If there are somehow some stable BH produced which don't interact with matter, it will almost be impossible to detect them, or even to find out that they were produced, given the superposition of events in LHC (so very difficult momentum balance).

There are more than charged particle detectors. There are calorimeters, which measure the energies of both charged and neutral particles (except neutrinos and muons, which do not stop), and outer muon identifiers. So neutrals are in fact detected and measured - the exception are neutrinos, but even here balancing momentum works in the vast majority of cases where the neutrino is energetic.

Momentum balance is not degraded by multiple interactions as much as you might think. The resolution on missing energy goes as the square root of the total energy in the detector, and typical events have much less total energy than "interesting" events. Combine these two facts and overlaps make a much smaller contribution than one might at first think.

There is a mass beyond which an invisible particle is undetectable because of kinematics. This is true for all experiments. However, the reach before the technique runs out of gas is much larger for the LHC than previous experiments.

 

[vanesch]

There are more than charged particle detectors. There are calorimeters, which measure the energies of both charged and neutral particles (except neutrinos and muons, which do not stop), and outer muon identifiers. So neutrals are in fact detected and measured - the exception are neutrinos, but even here balancing momentum works in the vast majority of cases where the neutrino is energetic.

I know, but calorimeters convert neutrals into charged particles. In the end, you only detect charged particles, even with a hadronic calorimeter, be it through nuclear showers.

Momentum balance is not degraded by multiple interactions as much as you might think. The resolution on missing energy goes as the square root of the total energy in the detector, and typical events have much less total energy than "interesting" events. Combine these two facts and overlaps make a much smaller contribution than one might at first think.

In the transverse direction, this is reasonable. But you'll have a hard time convincing me that you can do a momentum-balance in the longitudinal direction, especially with 10 events superimposed upon each other, and an unknown amount of momentum escaping in the beampipe. If I understand well, the LHC bet of superimposing events (to allow for higher luminosity) was that, as you say, events with large transverse momenta are relatively rare.

There is a mass beyond which an invisible particle is undetectable because of kinematics. This is true for all experiments. However, the reach before the technique runs out of gas is much larger for the LHC than previous experiments.

Ah ? I remember that this was one of the main problems at HERA. But then, at HERA, the collisions were asymmetrical.

 

[Vanadium 50]

I know, but calorimeters convert neutrals into charged particles. In the end, you only detect charged particles, even with a hadronic calorimeter, be it through nuclear showers.

Technically true, but misleading. Since everything eventually gets converted to electrical signals, one could just as well say the detectors only see electrons. Since if a high energy neutron, photon, or K-long were to be produced, it would be detected, I think it's entirely reasonable to say the LHC experiments detect neutral particles.

But you'll have a hard time convincing me that you can do a momentum-balance in the longitudinal direction

But that's not been either historically necessary or historically used. All detectors have holes in them in that direction, to get the beams in and out.

 

[George Jones]

electrons should, on the same argument, be regarded as having event horizons, and as being micro-black-holes, just as much as the Higgs.

No.

The Kerr-Newman solution in general relativity is determined by three parameters, mass, angular momentum, and electric charge. Using the values of these parameters for some astrophysical bodies gives spacetimes that have event horizons. The values of these parameters for an electron give a spacetime that doesn't have event horizons, i.e., give a spacetime that has a naked singularity. The solution also gives the correct gyromagnetic for the electron, as noted with a ! on page 883 of Misner, Thorne, and Wheeler.

All this is very interesting, but also very specualtive. I agree with vanesch; to make sense of things, we need a workable, accepted quantum theory of gravity.

 

[JustinLevy]

Since the Higgs has zero quantum number for everything, doesn't this have the same quantum numbers as a neutral black hole with no angular momentum?

Affirmative.

how could their cross sections differ at the same energy?

Cross sections are different, for different particles at the same energy because of the physical differences in a scattered particle in a given quantum state per solid angle.

I guess that is the crux of my confusion here. How can two particles with the same quantum numbers and same energy be physically different?

Those cross sections you provide are calculated with two different theories. One with the standard model, and the other with extrapolations using thermal hawking decay. Besides the fact that the smaller the black hole the further it will be from thermal decay if at all (thermal decay needs to give way at small scales for quantum mechanics to be correct) since thermal decay is in the classical spacetime limit, these are two completely different theories and comparing them like that seems completely unfair.

;------------------------------

As somebody else pointed out, the interactions with say photons are different between BH and Higgs - or at least, with a mini-classical BH and Higgs.

But as I pointed out earlier, the interaction of a photon with a neutral black hole is purely a gravitational coupling ... one that should be felt by all massive particles. And for GR to be the correct classical limit, this coupling needs to be the same for all particles of the same mass.

So no, the coupling between a neutral Higgs and a photon MUST be the same as a neutral black hole (with the same mass) and a photon.

So there may be gravity quantum numbers out there, which distinguish the Higgs from BH, but without a quantum theory of gravity, how are we going to even define the quantum numbers of a BH ?

Good point.
And after we have gone around this discussion for awhile, it looks like this has to be the answer.

If the Higgs and a black hole of the same mass are to be distinguished, there must be some quantum numbers which we don't know about yet in which they differ.

Very, very interesting!
And, since it would be very very unexpected to get a true black hole that far below the Planck mass, this seems to be a strong indication that there are some quantum numbers here we are missing. A good juicy little hint into the future!

Does anyone know string theory well enough to say what quantum numbers the Higgs and a black hole differ in, in that theory?

;------------------------------

But GR also provides that a point particle with a finite mass and non-zero spin (provided the spin is not too large) and non-zero charge will also have an event horizon (and an ergosphere).

So quarks and electrons should, on the same argument, be regarded as having event horizons, and as being micro-black-holes, just as much as the Higgs.

What is special about the Higgs?

Yes it is true black holes CAN have non-zero spin and charge. However, the amount of spin and charge they can have is limited with respect to their mass. If you run the numbers, you will find that NONE of the other standard model particles would have an event horizon (they have too much charge or angular momentum with respect to their mass). Only the Higgs would be a black hole according to GR.

why does it matter?

If something seems contradictory, usually something can be learned from it.

I think Vanesch has hit it on the head here. We have gained a strong suggestion that a more fundamental theory should provide new quantum numbers to resolve this situation. I find that fascinating. Don't you?

 

[tiny-tim]

No.

The Kerr-Newman solution in general relativity is determined by three parameters, mass, angular momentum, and electric charge. Using the values of these parameters for some astrophysical bodies gives spacetimes that have event horizons. The values of these parameters for an electron give a spacetime that doesn't have event horizons, i.e., give a spacetime that has a naked singularity.

ah … so an electron comes within the proviso I mentioned … "provided the spin is not too large".

But my main point still stands, doesn't it … a Higgs has no more reason to be a micro-black-hole than any other "point particle"?

All this is very interesting, but also very specualtive. I agree with vanesch; to make sense of things, we need a workable, accepted quantum theory of gravity.

Yes … I'm only concerned to point out that there is nothing special about the potential holeyness of the Higgs!

Thanks, George!

Yes it is true black holes CAN have non-zero spin and charge. However, the amount of spin and charge they can have is limited with respect to their mass. If you run the numbers, you will find that NONE of the other standard model particles would have an event horizon (they have too much charge or angular momentum with respect to their mass). Only the Higgs would be a black hole according to GR.

No … if they were "point particles" they could all be black holes … the Higgs would be the only non-naked black hole "point particle", that's all.

We have gained a strong suggestion that a more fundamental theory should provide new quantum numbers to resolve this situation. I find that fascinating. Don't you?

No … I find reality fascinating.

This speculation about the theory-that-is-yet-to-come that blends quantum theory with GR and miraculously produces micro-black-holes is boringly messianic.

 

[JustinLevy]

No … if they were "point particles" they could all be black holes … the Higgs would be the only non-naked black hole "point particle", that's all.

But your very definition of a black hole was that it had an event horizon. It seems like you are changing definitions merely to poo-poo the discussion.

As stated from the very beginning, the Higgs particle is unique from all the other standard model particles in this aspect.

No … I find reality fascinating.

This speculation about the theory-that-is-yet-to-come that blends quantum theory with GR and miraculously produces micro-black-holes is boringly messianic.

So you are not interested in thinking about something until it comes to you fully formed?
I'm sorry, but that seems reallly short sighted.

Heck, we even know the standard model is not exactly reality. We are doing the best with what we currently understand, it just happens we need to dig hard to get some insight with our current level of understanding gravity. I feel we learned something about the properties of such a theory in this discussion.

Even harder, people need to come up with ways to test these theories. It is our only probe of 'reality'.

But to each their own I guess.
Unless there is something more to add to this discussion, I consider my question here answered, so I guess this is done. Thank you everyone for your input.

 

[humanino]

But your very definition of a black hole was that it had an event horizon. It seems like you are changing definitions merely to poo-poo the discussion.

This is however the definition accepted by the majority at large, as you can see even on wikipedia. You have requested several times a definition : there you have it.

 

[tiny-tim]

But your very definition of a black hole was that it had an event horizon. It seems like you are changing definitions merely to poo-poo the discussion.

There you go again … referring without quoting.

I never defined a black hole … instead I said:

I'd prefer to define an event horizon …

and then I did so.

So you are not interested in thinking about something until it comes to you fully formed?

Even partly formed would do … but speculation about a totally unformed theory is philosophy, not physics …

if I want philosophy , I'll watch The Simpsons! :rofl:​

 

[JustinLevy]

But your very definition of a black hole was that it had an event horizon. It seems like you are changing definitions merely to poo-poo the discussion.

This is however the definition accepted by the majority at large, as you can see even on wikipedia. You have requested several times a definition : there you have it.

Oh come on!

What I asked for was:
Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?


If you are seriously considering any point particle as the "definition accepted by the majority at large" regardless of whether they have an event horizon, then we already have seen micro-blackholes according to the standard model. The very fact we are hoping to sift through the results of collisions at the LHC looking for black holes means that this can most assuredly NOT be the "definition accepted by the majority at large".

The wikipedia article on black holes does not help answer my question at all.

There you go again … referring without quoting.

I never defined a black hole … instead I said:

and then I did so.

So you're now trying to claim you gave an answer completely unhelpful for answering my question at all. How clever of you, and how useless. Why did you give it at all then? I assume it is related and then you complain when I assume so. Lovely.

Even partly formed would do … but speculation about a totally unformed theory is philosophy, not physics …

if I want philosophy , I'll watch The Simpsons! :rofl:​

This is not philsophy. If you haven't been paying close enough attention to see the physics being asked about and discussed, nor are willing to answer questions to further this, then I fail to see why you are hanging around here just to deride people.

I wish my topic hadn't been moved into this thread. Usually people on this forum are much easier to work with. But this thread seems to be (maybe due to influence from the frequent 'will the Earth be destroyed' comments that pop up) mostly for deriding and little for discussion.

 

[humanino]

What I asked for was:
Say a new particle showed up in the LHC. What properties would it have to have before you'd consider it a black hole?

Yes, but you also repeatedly asked for the definition (other people accept) of a classical black-hole itself. In all the books I checked, a classical black-hole is what has an event horizon. That is the definition I was referring to : the definition of a black hole.

Now maybe we can go on from here, take a look at Micro black hole (wikipedia). It points you for instance to Black Holes at the LHC. MBH (provided some are created) have a clear signature, the problem is to extract it above a huge background.

If you are serious about understanding these things, I strongly suggest as a minimum requirement the level of :
Warped Extra-Dimensional Opportunities and Signatures (Lisa Randall @ CERN Academic Training Lecture Regular Programme)

 

[JustinLevy]

Yes, but you also repeatedly asked for the definition (other people accept) of a classical black-hole itself. In all the books I checked, a classical black-hole is what has an event horizon. That is the definition I was referring to : the definition of a black hole.

I'm sorry, given tiny-tims's response I mistook your response to mean you were arguing black holes didn't need to have an event horizon. I didn't mean to give the impression I was asking for a classical definition, as I agree with you on the definition of that.

I'll check out the resources you suggested.
Thanks!

 

[Orion1]

I can identify at least four existential logical quantum numbers in General Relativity, based upon existential physical metric properties.

(gravity quantum number, mass quantum number, charge quantum number, angular momentum quantum number):
(g, m, q, j), (0 = non-existent, 1 = existent)

Photon: (0, 0, 0, 1)
Higgs: (0, 1, 0, 0)

In order for a gravity quantum number to exist as 1, then the mass must have an event horizon.

In order for quantum black holes to obey General Relativity, the logical values of these quantum numbers determines which metric a quantum black hole obeys.

The Schwarzschild radius r_s of an (4+n)-dimensional black hole: (1, 1, n, n)
$$r_s = \frac{r_p}{\sqrt{\pi}} \left[ \frac{E_{BH}}{E_p} \left( \frac{8 \Gamma\left(\frac{n+3}{2} \right)}{n+2} \right) \right] ^{\frac{1}{n+1}}$$

Schwarzschild metric: (1, 1, 0, 0)
$$c^2 {d \tau}^{2} = \left(1 - \frac{r_s}{r} \right) c^2 dt^2 - \frac{dr^2}{1-\frac{r_s}{r}} - r^2 \left(d\theta^2 + \sin^2\theta \, d\varphi^2 \right)$$

Reissner-Nordström metric: (1, 1, 1, 0)
$$c^2 {d \tau}^{2} = \left( 1 - \frac{r_{s}}{r} + \frac{r_{Q}^{2}}{r^{2}} \right) c^{2} dt^{2} - \frac{dr^{2}}{1 - \frac{r_{s}}{r} + \frac{r_{Q}^{2}}{r^{2}}} - r^{2} d\theta^{2} - r^{2} \sin^{2} \theta \, d\varphi^{2}$$

Kerr-Newman metric: (1, 1, 1, 1)
$$c^2 \mathrm d\tau^2 & = \left[ 1 - \frac{r_s r - r_Q^2}{\rho^2} \right] c^2 \mathrm d t^2 - \frac{\rho^2}{\Lambda^2} \mathrm d r^2 - \rho^2 \mathrm d\theta^2 \\ & - \left[ r^2 + \alpha^2 + \left( r_s r - r_Q^2 \right) \frac{\alpha^2}{\rho^2}\sin^2\theta \right] \sin^2 \theta \ \mathrm d\phi^2 \\ & + \left( r_s r - r_Q^2 \right) \frac{2\alpha\sin^2\theta}{\rho^2}\;c \mathrm d t\;\mathrm d \phi$$

Therefore, the distinguishing quantum number for a Standard Model quantum particle versus a Schwarzschild metric quantum black hole particle of the same mass is g, an event horizon.

Higgs quantum particle: (0, 1, 0, 0)
Schwarzschild metric quantum particle: (1, 1, 0, 0)

Reference:
http://www.youtube.com/watch?v=kVsZdgz5oFM"
http://en.wikipedia.org/wiki/Micro_black_hole"
http://en.wikipedia.org/wiki/Schwarzschild_metric"
http://en.wikipedia.org/wiki/Reissner-Nordstr%C3%B6m_black_hole"
http://en.wikipedia.org/wiki/Kerr-Newman_metric"
https://www.physicsforums.com/showpost.php?p=1871641&postcount=368"
http://en.wikipedia.org/wiki/Higgs_boson"
http://www.wissensnavigator.ch/documents/OTTOROESSLERMINIBLACKHOLE.pdf"

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RAYPOZ will exterminate all who oppose him,
Before the coming the sky will show signs.