Higgs Particles: Big Mass, Bigger Detection Challenge?

[Bowles]

They say Higgs particles are so hard to detect because their mass is so big. But when their mass is so big, wouldn't that make them easier to detect?

 

[pam]

but harder to produce.

 

[CraigD]

High mass means they decay very fast as well, but pam is correct, that the energy level associated with that mass is very hard to come by.

 

[Bowles]

But why the need of producing them? Don't they give all particles mass, so shouldn't they be ubiqious?

 

[malawi_glenn]

But why the need of producing them? Don't they give all particles mass, so shouldn't they be ubiqious?

But then they only exists as virtual particles.

And HOW would you detect a Higgs from the Higgs field?

 

[Bowles]

ahh, this virtual versus real particle business!

Keep forgetting and misunderstanding it.

So Higgs is sort of like the gluon field?

 

[malawi_glenn]

Higgs boson is the particle that gives other particle mass, by mediating between the Higgs field and the other fields. Rough speaking. There are also a varaity of models, with different Higgs bosons etc.

The basic thing one wants to detect is the decay of the (real) higgs boson. A Higgs boson are belived to be created in the proton + anti_proton annihilation at LHC.

 

[kdv]

ahh, this virtual versus real particle business!

Keep forgetting and misunderstanding it.

So Higgs is sort of like the gluon field?

In the sense that there is a quantum field associated to the Higgs like there is a quantum field associated to the gluon, to the electron, to each quark, etc.

So this Higgs quantum field permeates space and the other fields interact with it yielding a mass for all the particles (the massive ones).
However, this is only indirect evidence. To have a direct evidence of the Higgs field, we want to excite it and produce an observable excitation of the Higgs field which will appear as a Higgs particle. Until we produce and observe an excitation of the Higgs field we won't know it if really exists or if maybe the particle masses are produced by an entirely different process.

 

[Norman]

In the sense that there is a quantum field associated to teh Higgs like there is a quantum field associated to the gluon, to the electron, to each quark, etc.

So this Higgs quantum field permeates space and the other fields interact with it yielding a mass for all the particles (the massive ones).
However, this is only indirect evidence. To have a direct evidence of teh Higgs field, we want to excite it and produce an observable excitation of the Higgs field which will appear as a Higgs particle. Until we produce and observe an excitation of teh Higgs field we won't know it if really exists or if maybe the particle masses are produced by an entirely different process.

Spot on IMO.

 

[Jim Kata]

My question about the Higgs, is why haven't they found it. I mean its mass is < 225 GeV,

and a lot of the GUTS place it's value a lot smaller. I've seen it being possibly as light as

115 GeV. I mean with the Z boson particle weighing 91 GeV and the top quark 170 GeV

it seems like we're in the neighborhood of energies. If the LHC with its combined beam

energy of 14 TeV doesn't find it?

 

[Bowles]

I also like to add one question!

What particles are they smashing at another to get Higgs particle?

 

[malawi_glenn]

I also like to add one question!

What particles are they smashing at another to get Higgs particle?

See post #7 in this thread.

 

[Parlyne]

Higgs boson is the particle that gives other particle mass, by mediating between the Higgs field and the other fields. Rough speaking. There are also a varaity of models, with different Higgs bosons etc.

The basic thing one wants to detect is the decay of the (real) higgs boson. A Higgs boson are belived to be created in the proton + anti_proton annihilation at LHC.

Last I checked, the LHC is a proton/proton collider.

 

[malawi_glenn]

Last I checked, the LHC is a proton/proton collider.

Yeah that can be true, I might mix it with the FAIR project ;)

 

[ahrkron]

LHC is proton-proton.
Fermilab's Tevatron is proton-antiproton.

 

[Rade]

fyi, the LHC will also investigate photon-photon interactions--see here:
http://arxiv.org/abs/hep-ph/0702212

and photon-nucleus interactions--see here:
http://arxiv.org/abs/0706.3356

 

[malawi_glenn]

fyi, the LHC will also investigate photon-photon interactions--see here:
http://arxiv.org/abs/hep-ph/0702212

and photon-nucleus interactions--see here:
http://arxiv.org/abs/0706.3356

yes but the particles beeing accelerated towards each other are two protons.

 

[Coin]

My question about the Higgs, is why haven't they found it. I mean its mass is < 225 GeV,

and a lot of the GUTS place it's value a lot smaller. I've seen it being possibly as light as

115 GeV.

As I understand things there are people who work on the Tevatron who are actually convinced that the Tevatron is already producing/can produce Higgs Bosons, but that the events are lost among the background noise. If this is true then the Tevatron actually potentially could find the Higgs before the LHC does, but it would be really really hard to do so successfully. Maybe once the LHC finds the Higgs and we know what to look for then we'll be able to see the Higgs resonances in the Tevatron data?

 

[ZapperZ]

As I understand things there are people who work on the Tevatron who are actually convinced that the Tevatron is already producing/can produce Higgs Bosons, but that the events are lost among the background noise. If this is true then the Tevatron actually potentially could find the Higgs before the LHC does, but it would be really really hard to do so successfully. Maybe once the LHC finds the Higgs and we know what to look for then we'll be able to see the Higgs resonances in the Tevatron data?

This actually doesn't say much. For something to be convincing in the data, it must be at least a "5-sigma event". It has to be way beyond the background. No one is going to be convinced that it is there if it is barely above it, because a whole lot of things can cause a false signal at that level, and you also can't discount random coincidence. When you have a gazillion data points to deal with, random coincidence is more than likely.

Zz.

 

[Barmecides]

As I understand things there are people who work on the Tevatron who are actually convinced that the Tevatron is already producing/can produce Higgs Bosons, but that the events are lost among the background noise. If this is true then the Tevatron actually potentially could find the Higgs before the LHC does, but it would be really really hard to do so successfully. Maybe once the LHC finds the Higgs and we know what to look for then we'll be able to see the Higgs resonances in the Tevatron data?

Right. In principle Tevatron can produce Higgs, but there are two problems :
1- the probability to produce a Higgs boson (in the SM) is very small wrt other physics processes. So, the total number of expected events is small.
2- we need clean signature to disantangle Higgs from other processes (called background). For example H decay to b-bbar is largest probability but the background is so large that people cannot look for this kind of signature.
The same problems are at LHC, but more events are expected.