Standard Definition and 1000 Threads

https://arxiv.org/pdf/1903.00009.pdf "We present an explicit construction of O(1015) globally consistent string compactifications that realize the exact chiral spectrum of the Standard Model of particle physics with gauge coupling unification in the context of F-theory. Utilizing the power of...

Sorry, I'm not an astronomer. This question relates to the book "S." by Doug Dorst. I understand that the celestial coordinates have a zero-point at the vernal equinox. (0h, 0m, 0s RA, 0⁰, 0", 0' Dec.) I also understand that it's possible to map these coordinates to spherical, or...

We define the application $T:P_2\rightarrow P_2$ by $$T(p)=(x^2+1)p''(x)-xp'(x)+2p'(x)$$ 1. Give the matrix $\displaystyle\left[T\right]_\infty^\infty$ in the standard basis $\alpha=(x^2,x,1)$ 2 Give the matrix $\displaystyle\left[T\right]_\infty^\infty$ where...

Does anyone know the reasoning behind the decision to use 37 degrees for the conical taper on an AN fitting? I understand this is a standard dimension for the fittings, but I am hoping to get a little background on how this came to be.

Hi. I'd like to ask what are the differences between Particle Physics, Quantum Field Theory and the Standard Model. I see these names of physics courses but I want to confirm if I understand the difference. My understanding is that when students learn particle physics in their undergraduate...

Hello there, I am studying Taylor series, and in the slides given to us we calculated the taylor series of ln $(\frac{1+x}{1-x} )$ = ln(1 + x) − ln(1 − x), by using standard Taylor series of ln(1 + x). The notes then proceed to say : " It can be shown that every positive real number t can be...

I'm just trying to figure somethings out concerning the accelerating expansion of the universe and the measured redshift, etc. If a light emitting object moves away from us, because of the expansion of the universe, the speed of that object causes a redshift in this light. But this light, from...

I'm currently doing a course on the Standard Model and I think I've gotten confused on some of the symmetries and resulting currents. Here's my current understanding: Before SSB: Electroweak - U(1) symmetry on fermion spinors and Higgs complex doublet, 1 conserved current Electroweak - SU(2)...

Hey there, First time on this forums, looking forward to some interesting discussions :) I am currently trying grasp the concepts of error propagation and standard deviation in relation to experimental physics. I have some data set and i want to determine the difference between the measured and...

Previously I posted a problem concerning Electron-neutrino scattering, but as I couldn't describe the problem clearly, so I am trying to post the problem using latex codes to present it in the correct way. For a couple of months, I am trying to calculate the invariant amplitude of the Neutrino...

For a couple of months, I am trying to calculate the invariant amplitude of the Neutrino electron scattering in the standard model (SM) approach where I am not considering any kind of approximation and using the SM propagator for W Boson and Z Boson. I tried to do as following, find out the...

Homework Statement (b) A nuclear research reactor produces radiation for neutron scattering measurements. A safety procedure shuts the reactor down if a radiation level monitoring detector measures more than 3 counts per minute. In a test, 156 counts are recorded during a random 24 hour...

Homework Statement A switching network has 4 inputs and a single output (Z) as shown in the figure below. The output Z is 1 iff the binary number represented by ABCD ( A is the MSB) is an even number greater than 5. Find : a) The standard POS of Z (abbreviated form). b) The standard SOP of...

There is a proposal for a generalized lattice standard model by Juven Wang and Xiao-Gang Wen. Could this be correct? I've put this under BTSM because it also mentions grand unified models. https://arxiv.org/abs/1809.11171 A Non-Perturbative Definition of the Standard Models Juven Wang...

Homework Statement I know how to approach this problem; however, I'm just confused as to why we consider that R^2 is a vector space over the field R, and not Q or any other field for this question? Standard basis vectors: e_1, e_2 or i,j

Hey. I am planning on doing some research, where I predict a change based on different types of risk. The question is simple. Can I use values of standard deviation as independent variables in a linear regression analysis (OLS)? The standard deviation values over time will be calculated in...

In most popular explanations of entanglement, the quantum information of an entangled two-particle system changes without regard to the distance between the two particles. The following paper seems (to my unprofessional eye) to be questioning this interpretation...

Hello. I have some questions concerning the Standard Hot Big Bang model versus the Inflationary model. I've read that the Standard model cannot solve the Horizon and Flatness problems but Inflationary cosmology can. Firstly, is this so? Any replies that are pitched at my basic level of...

Homework Statement Homework Equations Chebyshev's Theorem: The percentage of observations that are within k standard deviations of the mean is at least 100(1 - (1/k2))% Chebyshev's Theorem is applicable to ANY data set, whether skewed or symmetrical. Empirical Rule: For a symmetrical...

Homework Statement in acid medium the standard reduction potential of NO converted to N2O is 1.59V .its standard potential in alkaline meduim at 298k would be? Homework Equations a)2NO+2H ---> N2O +H20 E=1.59 b)2NO + H2O ---->N2O + 2OH- E=x c)2H2O---->2H+ + 2OH- E=0.826 (calculated...

Homework Statement If E°(Fe2+/Fe) is x1 and E°(Fe3+/Fe) is x2 then find E°(Fe3+/Fe2+) 2. The attempt at a solution We need E for Fe3+ + e ----> Fe2+. We are given Fe2+ + 2e----->Fe is x1. Reversing will give Fe--->Fe2+ + 2e (-x1)...(i) also, Fe3+ + 3e----->Fe is x2, ...(ii) multiply (ii) by 2...

Weinberg considers (p.68 QFT Vol. 1) particles with mass M > 0. The Little Group is SO(3). He wants to calculate the rotation W(Λ,p) ≡ L-1(Λp) Λ L(p). He says that for this we need to choose a standard boost L(p) which carries the four momentum from kμ = (0,0,0,M) to pμ. He then shows the...

In high school, I was taught that the standard deviation drops as you increase the sample size. For this reason, larger sample sizes produce less fluctuation. At the time, I didn't question this because it made sense. Then, I was taught that the standard deviation does not drop as you increase...

Hi, I'm trying to grasp the standard derivation of the quantum Zeno effect. But my calculus is limited. I would love some assistance! Schroedinger evolution tells us that the state at time t, given the initial state at time t=0, is: |\psi_t\rangle = e^{-i H t} |\psi_0 \rangle We can then...

Hi. I have a question about covariance matrices (CMs) and a standard form. In Ref. [Inseparability Criterion for Continuous Variable Systems], it is mentioned that CMs ##M## for two-mode Gaussian states can be symplectic transformed to the standard form ##M_s##: ## M= \left[ \begin{array}{cc}...

(apologies for re-posting, I am unable to find my original thread.) A material which has a Young's modulus of elasticity of 250 GN m-2 and a poisons ratio of 0.32, calculate: (a) the bulk modulus of the material 
 Relevant equation, K=E/3(1-2v) Inputting our known values...

Hello. Math is not my strongest part, yet, so I will be very grateful for your help and for giving the answer in sort of "plain" English, meaning that it will be great if you don't go too deep into the rabbit hole using difficult terminology, as these distribution issues are truly difficult for...

I've managed to work out the below for the sample standard deviation. Any error's that I should be aware of? Homework Statement The ultimate tensile strength of a material was tested using 10 samples. The results of the tests were as follows. 711 N 〖mm〗^(-2),732 N 〖mm〗^(-2),759 N...

I'm trying to make sense of the derivation of the Klein-Gordon propagator in Peskin and Schroeder using contour integration. It seems the main step in the argument is that ## e^{-i p^0(x^0-y^0)} ## tends to zero (in the ##r\rightarrow\infty## limit) along a semicircular contour below (resp...

Hello, This algorithm overall is probably more complicated than is correct for the pre-university forum but this question is about a relatively simple aspect of the calculations so I hope that this will be the proper place to ask. I am writing a little program to do some computational geometry...

Homework Statement Homework Equations None. The Attempt at a Solution I know that the standard matrix of a counterclockwise rotation by 45 degrees is: [cos 45 -sin 45] [sin 45 cos 45] =[sqrt(2)/2 -sqrt(2)/2] [sqrt(2)/2 sqrt(2)/2] But the problem says "followed by a projection onto the line...

Hi everyone. I'm looking for a good book or some good source of informations about the stantard solar models, but i can only find compact stars stuff. Do you guys have any sugestions ?

If we measure one conjugate variable in an uncertainty relation precisely , i.e., so its standard deviation is zero, then by the HUP the sd of the other one is either infinite or undefined. But what about the cases when the other conjugate variable has limits: e.g., there cannot be an infinite...

I am reading D. J. H. Garling's book: "A Course in Mathematical Analysis: Volume II: Metric and Topological Spaces, Functions of a Vector Variable" ... ... I am focused on Chapter 11: Metric Spaces and Normed Spaces ... ... I need some help with Corollary 11.1.5 ... Corollary 11.1.5 reads...

I am reading D. J. H. Garling's book: "A Course in Mathematical Analysis: Volume II: Metric and Topological Spaces, Functions of a Vector Variable" ... ... I am focused on Chapter 11: Metric Spaces and Normed Spaces ... ... I need some help with Corollary 11.1.5 ... Corollary 11.1.5 reads as...

I just wanted to get this out of my system. I'm not talking about the main article on SM but the mathematical formulation one: https://en.wikipedia.org/wiki/Standard_Model_(mathematical_formulation) Very, very hard to find good summarized material on SM out there. It's either good coverage but...

I have been doing a study for a couple of years now on the off center fed dipole. I was very much in the dark on what to expect in the relationship between the off center fed (ocf) and a regular dipole. I asked many questions and most of the time I jumped to the wrong conclusions. I decided...

Homework Statement The same potato chip company reports that their bags of family sized chips each follows an approx. Normal distribution with a mean of 10.72 ounces and a standard deviation of 0.2 ounces. If the company wants to ship these chips into boxes that contain 6 bags, what would be...

Not the best at physics but trying to understand the standard model. So can someone please tell me if this is right or not and if not, can you explain me why? Higgs bosons reacts with everything that has mass. Electromagnetic force reacts with everything that has charge. Weak force reacts with...

I am an American author, working on a revision for my Theory of Machines textbook. In the past, I used only US Customary units, but now see a need to introduce SI units. This is particularly a problem with regard to gear standards. An internet search shows that there are dozens of SI-based gear...

Hi All, This is probably trivial. What is the difference between techniques such as Linear/Logistic Regression, others done in ML , when they are done in Standard software packages : Excel ( incl. add-ons ), SPSS, etc? Why use ML algorithms when the same can be accomplished with standard...

Homework Statement Homework EquationsThe Attempt at a Solution ## \frac 1 2 m<v_x^2> =\frac 1 2 k_BT , \\ \sqrt{ <v_x^2>} = 556~ m/s ## So, I guess that the standard deviation should be less than rms speed. So, the option is (a) ## \left< ax + b \right> = a\left<x\right> + b...

I don't understand why does the standard deviation of a t-Distribution decreases as the degree of freedom (and, thus, also the sample size) increases when the sample standard deviation underestimates the population standard deviation?

This T-shirt I bought at a physics conference displays the following equation. It looks like the Lagrangian of the Standard Model of particle physics but I only recognise lines 1 (electroweak) and 3 (Higgs mechanism). What are lines 2 and 4 and what is/isn't included? eg. are quarks, gluons...

Hi , this is my equation : μA= μA0 + RTlnaA A is the asphaltene in toluene solution . i want to calculate μA in different temperatures. where can i get μA0 and aA? tables? other equations? μA0 is the standard chemical potential of asphaltene and aA is the asphaltene activity in solution.

I know that the standard deviation of sample = standrad deviation of population divided by sqrt(n) ... However , in the following question , i don't know how to identify whether the standard deviation given is standard deviation of sample or standard deviation of population ... Can anyone help...

When working a proof, I reached an expression similar to this: $$\int_{-\infty}^{\infty} \frac{\mathrm{e}^{-a^2 x^2}}{1 + x^2} \mathrm{d}x$$ I've tried the following: 1. I tried squaring and combining and converting to polar coordinates, like one would solve a standard Gaussian. However...

Homework Statement If one bar of a histogram has been generated with ##n## entries from a total of ##x## measurements, i.e. the event occurs randomly ##n## times in the ##x## event interval, then what is the standard deviation of values in this bar? Let ##k## be the range of values that could...

Can someone guide me through the process of solving the following? Many thanks. "Given the set {11, 12, 13, 14, 15}, by approximately how much does the standard deviation change if the least value is decreased by 2 and the greatest value is increased by 2?" These questions are all over the...

Hi, All. I'm trying to re-familiarize myself with standard deviations. Any resources? I'm reading through the threads here and trying to figure out the following: "n is a positive integer. What is the standard deviation of 10 consecutive positive multiples of n. And what is the standard...