Gamma Definition and 714 Threads

Quite unexpectedly, it seems that the Fermi Gamma-ray Burst Monitor spotted what appears to be a hard gamma-ray burst about 0.4s after the LIGO GW event, lasting about 1s: http://arxiv.org/abs/1602.03920 This is not expected from a black hole merger (and as a black hole sceptic, I find it very...

If there are bacteria that can get their energy from gamma rays (thus thriving on nuclear reactors), can multicellular life do it too? If so, wouldn't that broaden the parts of the universe where life could arise?

So say I have a truncated normal. That is, N(mu,sigma) that is from 0 to infinity only. I need to find a Gamma such that a constant C*Gamma(A,B) is always above N(mu, sigma). How would I go about finding such a A, B that would work given fixed mu and sigma?

Is there any gamma decay or x-ray decay in Actinium series, Uranium series or Thorium series? On Wikipedia, it only shows alpha and beta decay, does it mean high energy photon decay (gamma or x-ray) exists in each process? Thank you! https://en.wikipedia.org/wiki/Decay_chain#Actinium_series

I've been googling explanation for gamma ray bursts but couldn't find any that explain how and why the jets actually form, in one website I read that the jets have to be there to "carry off momentum and keep the black hole from spinning too fast", and no other details are mentioned in that...

If we can not use gamma rays to detect Dark Matter what can we use? http://www.sciencedaily.com/releases/2016/02/160203110928.htm Studies by two independent groups from the US and the Netherlands have found that gamma ray signals from the inner galaxy come from a new source rather than from...

Hi Everybody! Just have read in the Report into the death of Alexander Litvinenko https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/493860/The-Litvinenko-Inquiry-H-C-695-web.pdf I'm very surpised to see that namely Gamma Spectrometry was used while only 1 in 100,000...

Hello, I have attached a picture of the integral I am solving. I understand at the end how they turned the function (in the second to last step) into gamma(2) BUT what I do not understand is how you can simply just remove the (2/theta) out of the exponent of e, turn it into gamma(2) then divide...

Pair Production questions: 1) When a gamma ray photon pair produces an electron and a positron, do the two particles always have the opposite spin? That is, one always has +1/2(h-bar) spin and the other has -1/2(h-bar) spin? 2) Other than charge and spin, what are some other notable...

I want to show that $$\int_0^{\infty} \frac{ds}{s-q^2} \frac{s^{-1-\epsilon}}{s-t \frac{z}{1-z}} = \Gamma(1-\epsilon) \Gamma(\epsilon) \frac{1}{t \frac{z}{1-z} - q^2} \left((-t)^{-1-\epsilon} \left(\frac{z}{1-z}\right)^{-1-\epsilon} -(-q^2)^{-1-\epsilon}\right) $$ I have many ideas on how to...

I found an article, titled Electromagnetic Decay of the Σ0(1385) to Λγ , in the arXiv telling that the reaction Σ0→Λ+γ can happen through electromagnetic interaction. However, if I examine the conservation of parity. Parity on the left side is even(P(Σ0)=+), but that on the right side is...

1. Homework Statement A piece of work I am doing for college (UK college that is) has me investigating the inverse square law for gamma radiation. I have collected data and the graph comes out looking right. I want to create a linearised graph of the data to investigate the results further. If...

Trace of six gamma matrices I need to calculate this expression: $$Tr(\gamma^{\mu}\gamma^{\nu}\gamma^{\rho}\gamma^{\sigma}\gamma^{\alpha}\gamma^{\beta}\gamma^{5}) $$ I know that I can express this as: $$...

Homework Statement There is a radioactive source plaed in front of the GM counter to predict the kind of radiation emmitted by the source. 1 : When the GM counter moves 5 cm away from the source, the count rate drops significantly. 2 : When a 5mm aluminium sheet is inserted...

Hello everyone, I found in the PDG booklet that pi 0 decay into e+ e- gamma is more likely to happen than to e+ e- only ..is there a reason that favorises the first decay?

Homework Statement Suppose X ~ Gamma(α, scale = β and that Y = kX with k > 0 a constant. Show that Y ~ Gamma(α, scale = kβ). Homework Equations Gamma distribution, etc. The Attempt at a Solution λ = \frac{1}{β} f(x) = \frac{λ^{α}}{Γ(α)}x^{α-1}e^{-λx} =...

In conjunction with diving, a mixture of helium and oxygen called heliox. It will form the background to the following model invoice. Suppose that 1 mole of He and 1 mole of O2 is compressed as fast at half the volume that no heat exchange with the environment have time to take place...

I have heard that in my next semester, our quantum mechanics teacher will be giving a great emphasis on difficult integrals with the most of them having to do with gamma functions. Does anybody know a book(or any other source) that I can learn about and practice gamma functions integration...

From my understanding gamma rays can damage metal, making it brittle. Fortunaly, this appears to be little, but sill if you have a lot (like in p-D fusion) it becomes a serious hazard. The question is, how much? Specificly I need to know how much damange it does in compairison to Neutron...

Hi everyone! So, I know that for a certain Synchrotron I have an output value of 1.5GeV/u for Uranium-238 particles, with a charged state of 28+ (## ^{238}U^{+28} ##). For this ion I would like to calculate the rest energy and the associated relativistic gamma factor. My approach was the...

This is given in Mathematical methods for physicists by Arfken and weber, while defining a property of gamma function, I have no idea how the term in the red circle becomes 'z' in the final step, please help

My question is, if X-Ray and Gamma rays overlap in the EMR spectrum, then how can they be classified differently. I have read about different energy levels but I'm just afraid I'm missing something is that the only difference?

Today's APOD shows an animated visualization of a gamma ray flare detected by The Fermi Space Telescope. The video says, "each circle represents one gamma ray" That language suggests single photon detection. Is that correct?

I have just done an efficiency calibration measurement for the HPGe detector of a whole-body counter. Ba-133 and Eu-152 were the calibration nuclides. For a calibration at low energies I thought of using the X-ray emissions of both nuclides as well. However, the result looks quite bad - see the...

I was just wondering... Is it possible to explain the J,C,P of the \pi^0, J^{CP}=0^{+-} just from the diphoton decay? \pi^0 \rightarrow \gamma \gamma The C is straightforward. However are the J,P deduced by this interaction alone?

Hi every one, What is the smooth gamma ray energy spectrum in gamma radiation? And, What is the algorithm of smooth gamma spectrum? Thank every one to much!

The 300 series of stainless steel is austenitic meaning that the iron in the steel is gamma iron. This means that if it is magnetic it is only the weak magnetism from the nickel. I read the wikipedia article on allotropes of iron and it says that gamma iron occurs when the iron is heated to...

Question Find the posterior probability that the next two observations y4 and y5 will both be zero? Where the prior distribution is a gamma with parameters (a,b) and the sample is of size of 3 taking from a poisson disribution with parameter V. So far I have shown that the posterior...

Why is the central electrode in a Geiger-Muller tube always positive (and not negative)? Many thanks!

So it seems straightforward to me that if time dilated, then so would size, mass and energy, but I don't know how to prove that mathematically. I understand the concepts of special relativity and the lorentz transform, and why it is applied to time, but I can't recall or figure out why Einstein...

Homework Statement Automobile accidents occur in the United States over a 72 hour holiday period like events in a Poisson process with parameter lambda=10/hr. V is the time until the 10th accident a) what is expected value of V or E[V] and standard deviation? b) What is the probability that V...

Homework Statement Fluorine-18 is an isotope of fluorine often used in positron emission tomography, as it undergoes beta negative decay. a) Determine the decay equation for fluorine-18.b) If the positron emitted collides with an electron, it annihilates the electron and emits 2 gamma...

Hello everybody, In one of my assignments I have lost a substanial portion of the grade for one problem because I haven't assumed that the energy of a Gamma ray = hf, I thought this was wrong, and that nothing in the statement says that it consists of only one photon. In fact, it says "high...

This question straddles this forum and the "Beyond the Standard Model" one a bit, so if a mentor thinks it belongs better elsewhere, please feel free to move it. I've seen references in the "popular science" press about the possibility of indirectly detecting dark matter by looking for gamma...

I'm doing high school physics and if a question says something like: A radioactive source gives count rate of 110 counts per second Can you say that the ACTIVITY is also 110 bq? My second question is how would a gieger counter detect gamma radiation? It is the least ionising of all three...

Homework Statement Write ##\int_{0}^{1}x^2(ln\frac{1}{x})^3 dx## in terms of the gamma function 2. Relevant equation ##\Gamma(p+1)=p\Gamma(p)## The Attempt at a Solution Say ##x=e^{-u}## one would eventually obtain the integral ##\int_{-\infty}^{0} u^3 e^{-u} du## STEPS: ##x=e^{-u}##...

Hi all, I make some exercises in particle physics but I'm stuck in two problems related to Gamma matrices identities, First: the Fermion propagator ## \frac {i } { /\!\!\!p - m} = i \frac { /\!\!\!p + m } { p^2 - m^2} ## So how ##/ \!\!\!\!p ^2 = p^2 ## ? Where ## /\!\!\!p = \gamma_\mu p^\mu...

Hello, everyone. After my discovery some time ago of the gamma function \int_a^b x^{-n}e^{-x}dx (where b = infinity and a = 0...sorry, haven't quite figured out LaTex yet...and actually the foregoing is the factorial function [I think it's silly that the argument has to be shifted down by...

Hello :) I hope its ok/allowed to ask for help.. Since I'm looking for a software I don't know where I should post it :/ I would like to know if you have an idea whether its possible to download the open soure software called "SAANI" which is described here...

Hey! So I'm self studying mary boas's mathematical methods book and I've come across this integral: \int _{0}^{\infty }e^{-x^4}dx and I'm suppose to write this using the gamma function. The hint given states to let x^4 = u. And the answer is: \Gamma \left( \dfrac {5} {4}\right) I tried...

I tried solving this question this way: Gamma(n+1/2) =(n+1/2-1)gamma(n+1/2-1) =(n-1/2)gamma(n-1/2) =(2n-1)/2 gamma (2 n-1)/2 Don't know what to do next

http://arxiv.org/pdf/1503.02320v1.pdf This paper discusses the emission of gamma rays from a neighboring dwarf galaxy. My understanding is that there is no conventional explanation of gamma ray emission. So there is interest in pursuing a possibility that these emissions are from dark matter...

Or, more specifically, what determinates the frequency of the photons emitted by a such a collision. I know that the number of photons produced depends on the spin and energy states of the initial particles.

Homework Statement In this lab various thicknesses of a few materials are placed between a source of gamma radiation and a couple different detectors. It is reasonable to assume that some small change in the thickness of the shielding would produce a proportional change in the intensity of the...

So I have a problem where I'm given the decay rate of a sample which contains Cs137, 10 mCi, and I'm basically given the percentage of radiation detected by the detector. But the wording of the question is: "What count rate would be observed in a perfectly efficient gamma detector" Sounds to...

Homework Statement I am working through some maths to deepen my understanding of a topic we have learned about. However I am not sure what the author has done and I have copied below the chunk I am stuck on. I would be extremely grateful if someone could just briefly explain what is going on...

Hi all, Does anybody work with FeynArts? I try to generate the amplitude of ## \mu \to e \gamma ## process by : tops = CreateTopologies[1, 1 -> 2] ins = InsertFields[tops, F[2, {2}] -> {F[2, {1}], V[1]}] But when I type: Paint[ins] it returns out[] FeynArtsGraphics[{"\\mu"} -> {"e"...

Hi, I came across a question in an exam which I couldn't really relate to any topic of physics, that I had studied. It goes like this- A detector is used to count the number of gamma rays emitted by a radioactive source. If the number of counts recorded in exactly 20 seconds is 10000, the...

Hey guys, I'm trying to find a conditional distribution based on the following information: ##Y|u Poisson(u \lambda)##, where ##u~Gamma( \phi)## and ##Y~NegBinomial(\frac{\lambda \phi}{1+ \lambda \phi}, \phi^{-1})## I want to find the conditional distribution ##u|Y## Here's what I've got so...

Hello, I would like to know, what happen with accretion (cloud) when drop toward a black hole. In Bondi case and terminology. If I understand: 1) We describe the cloud falling to star (black hole) by EoS P(\rho)=K\rho^\Gamma . 2) This accretion is steady it means \dot{M}=4\pi r^2u\rho=const...