What is Gamma: Definition and 711 Discussions

Gamma (uppercase Γ, lowercase γ; Greek: γάμμα gámma) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop /ɡ/. In Modern Greek, this letter represents either a voiced velar fricative or a voiced palatal fricative.
In the International Phonetic Alphabet and other modern Latin-alphabet based phonetic notations, it represents the voiced velar fricative.

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  1. P

    Exploring Gamma Waves and Their Impact on Human Cells

    hi my friends I want some informations to study about gamma wave and interactions of it on humans cells.thancks alot.
  2. E

    Calculate Gamma Distribution: 5% at $627, 95% at $1444

    On the included link, it is calculated that 5% of payouts are around $627 and 95% of payouts are at $1444. I would appreciate if someone can direct me as to how the came up with this answer. http://www.brighton-webs.co.uk/distributions/gamma.asp"
  3. B

    Determine pdf of function with gamma pdf

    Homework Statement Hi Guys, I have been given the following The random variable X has a gamma (\alpha,\beta) distribution; ie X has pdf f_{X}(x)=\frac{x^{\alpha-1}e^{\frac{-x }{\beta}}} {\Gamma (\alpha)\beta^{\alpha}}\text{for }x \geq 0 (a) Determine the pdf of...
  4. K

    Gamma Function: Understanding \Gamma(n) = (n-1)!

    \Gamma(n) = (n-1)! Corrrect?
  5. K

    How Are Gamma Rays Absorbed in Materials Used Practically?

    I need to know the practical applications of the absorption of gamma rays in materials.
  6. B

    Reps of lorentz group and pauli and gamma matrices

    I'm very confused By performing a lorentz transformation on a spinor \psi\rightarrow S(\Lambda)\psi(\Lambda x) and imposing covariance on the Dirac equation i\gamma^{\mu}\partial_{\mu}\psi=0 we deduce that the gamma matrices transform as S(\Lambda)\gamma^{\mu}...
  7. E

    Understanding Gamma Distributed RV: Finding Shape and Scale Parameters

    Hello, When writting a gamma distributed RV we need to know the shape and scale parameters. How to find the value of these parameters? Thanks in advance
  8. M

    High Energy Gamma Rays: Interaction w/ Matter

    Is there any on-line reference which describes the interaction of high energy (> 100 Mev) gamma rays with matter. These are gamma rays from gamma ray bursts, etc. in contrast to low energy from nuclear radiation.
  9. E

    How was the result of the incomplete gamma function in the paper achieved?

    Homework Statement I read in a paper that: \Gamma\left(c,\,d\frac{x+e}{x-y}\right) = (c-1)!\,exp\left[-d\frac{y+e}{x-y}\right]\,exp[-d]\,\sum_{k=0}^{c-1}\,\sum_{l=0}^k \frac{d^k}{k!}{k\choose l}\left(\frac{y+e}{x-y}\right)^l Homework Equations But the incomplete gamma function...
  10. A

    Gamma Function in closed form?

    Could you consider the gamma function to be a closed form representation? If I could express a numerical series in terms of the gamma function, would it be considered a closed form representation?
  11. D

    Data Analysis: Gamma ray attenuation

    Hello, I'm attempting to analyse the data recovered from an experiment that I performed in lab, but I'm having some problems understanding how to properly apply the statistical methods learned to this specific problem. Essentially, the experiment consisted of placing a source of gamma rays...
  12. pellman

    How do we tell how far away a gamma burst was?

    http://news.yahoo.com/s/afp/20090219/sc_afp/sciencespaceastronomy This was one was supposed to be 12 billion LY away. How do we tell? If it is using red shift, how do we know what it looks like unshifted?
  13. malawi_glenn

    The Gamma Matrix Trace Paradox: A Conundrum in Spinor Calculations

    gamma matrix trace Paradox?? Hello, i tried to evaluate this particular little guy: \text{Tr} (\gamma ^0 p_\mu \gamma ^\mu \gamma ^0 q_\nu \gamma ^\nu ) using these identities: \gamma^0 \gamma^0 = I \text{Tr} (\gamma^\mu \gamma^\nu \gamma^\rho \gamma^\sigma) = 4 (g^{\rho \sigma} g^{\mu \nu}...
  14. N

    Is Hydrogen Gas Transparent to Gamma Rays? And What About Xenon Gas?

    I remember reading before that hydrogen gas is "transparent" to gamma rays. What does this mean? I know it has something to do with the gamma rays not heating the hydrogen. Also, would Xenon gas be transparent to gamma rays?
  15. O

    J shock in a gas for gamma = 7/5

    Homework Statement For the case of a strong shock propagating into a gas with \gamma=7/5 What is the ratio \rho2/\rho1 Homework Equations \rho\ u=constant P+ \rho\ u^2=constant \frac{1}{2} u+ \frac{\gamma }{\gamma -1}\frac{\ P}{\rho} = constant The Attempt at a Solution I can use the 3...
  16. J

    Stirling approximation for gamma function

    How to prove that this formula is correct: \lim_{x\to\infty} \frac{\Gamma(x+1)}{\sqrt{2\pi x}\big(\frac{x}{e}\big)^x} = 1 I have seen a proof for this: \lim_{n\to\infty} \frac{n!}{\sqrt{2\pi n}\big(\frac{n}{e}\big)^n} = 1 but it cannot be generalized easily for gamma function. The proof...
  17. J

    Is the Gamma Function Convergent for Re(z)<0 and Im(z)≠0?

    \Gamma(z) = \int\limits_0^{\infty} t^{z-1} e^{-t} dt I can see that if \textrm{Re}(z)>0, then the integral converges, and that if \textrm{Re}(z)\leq 0 and \textrm{Im}(z)=0, then it diverges. However, I found the case \textrm{Re}(z)\leq 0 and \textrm{Im}(z)\neq 0 more difficult. t^{z-1} =...
  18. A

    Proving Gamma Function: Get Help Now

    can anybody help me to proove gamma(n+1/2)=(2n)!*sqrt(pi)/((4^n)*n!) thank you
  19. P

    Gamma spectroscopy (Scintillator)

    I know that theorically the numbers of counts between compton edge and the photopeak must be zero. In practice it doens't occur. Why? Thanks in advance!
  20. T

    Approximating Gamma Function: Numerically Calculate \(\frac{3}{2}\)

    1. Numerically approximate \Gamma(\frac{3}{2}). Is it reasonable to define these as (\frac{1}{2})!? 2. Show in the sense of question 1. that (\frac{1}{2})! = \frac{1}{2}\sqrt{\pi} at least numerically. How am i supposed to attempt this numerically? given that i do not know additional...
  21. T

    Mathematica Comparing Gamma & Factorial Functions in Mathematica

    Why does Mathematica sometimes give Gamma, the funtion and sometimes !, the factorial? What is the differences?
  22. D

    Gamma Ray Bursts and Gravitational Radiation

    Okay, I'm writing a short response of about one page right now. Here's the question: Regarding soft gamma ray repeaters, 1. Is there any connection between the electromagnetic radiation and gravitational radiation? (specify: luminosity of the source? Thresholds?) and 2. How much...
  23. S

    Finding the Critical Velocity for Special Relativity Effects

    Homework Statement For what value of v does Gamma (G) =1.0100? Observe that for speeds lower than this value, time dilationand length contraction are effects amounting to less that 1% Homework Equations L=Lp/G=Lp(1-(v^2/c^2))^2 The Attempt at a Solution I do not know where to...
  24. J

    Gamma ray burst, LQG and String Theory

    I was reading this: https://www.physicsforums.com/showthread.php?t=181830 I was wondering if there is any up to day info about the speed of gamma ray burst that could confirm or debunk these claims. Or are LQG and String Theory in troubles?
  25. A

    Solve this with lower incomplete gamma function

    Homework Statement \int e^{-\frac{2Zr}{a}}*r^{-1}dr Boundaries:[0,R] Homework Equations --- The Attempt at a Solution I tried to solve this with lower incomplete gamma function and got \gamma(0,\frac{2ZR}{a}) which is infinite i think. Z=81,a:Bohr radius,R=r0*A^(1/3)...
  26. marcus

    More about that gamma burst (the brightest ever recorded)

    http://arxiv.org/abs/0810.2481 Gamma-Ray Burst at the extreme: "the naked-eye burst" GRB 080319B P.R. Wozniak, W.T. Vestrand, A.D. Panaitescu, J.A. Wren, H.R. Davis, R.R. White (Los Alamos National Laboratory) accepted for publication in Astrophysical Journal (Submitted on 14 Oct 2008) "On 19...
  27. E

    What's the difference between gamma rays and x rays?

    what's the difference between gamma rays and x rays?
  28. wolram

    Exploring the Most Distant Gamma Ray: Insights from GRB 080913

    http://www.sciencedaily.com/releases/2008/09/080919185809.htm * "This is the most amazing burst Swift has seen," said the mission's lead scientist Neil Gehrels at NASA's Goddard Space Flight Center in Greenbelt, Md. "It's coming to us from near the edge of the visible universe."...
  29. B

    Gamma function to Stirling Approximation

    Homework Statement Show that the integrand of \Gamma(s+1)=\int_{0}^{\infty} t^se^{-t}dt may be written as e^{f(t)} where f(t)=s\ln{t}-t. Show that f(t) is maximum at t=t_0 and find t_0. If the integrand is sharply peaked, expand the integrand about this point (ie Taylor expansion) and...
  30. D

    Calculating Posterior distrib of gamma funct

    guys can u please help me out in calculating the posterior distib of the gamma function of form : p(lambda/alpha,beta) = (beta^alpha)*lambda^(alpha-1)*(e^(-beta*lamda)))/gamma(a) lambda>0 mean=alpha/beta mode = (alpha-1)/beta ;alpha>0 the integration seems really tuff which makes...
  31. C

    NASA Gamma ray map of the galaxy completed by NASA

    Very cool image. Does anyone know, is anything in the information we got from this so far at all surprising? Is it likely we will learn anything about gamma ray bursts from this or is more information
  32. T

    How do the Veneziano amplitudes explain the strong force?

    I Heard That the gamma function explains the strong nuclear force . \Gamma \left( z \right) = \int\limits_0^\infty {t^{z - 1} } e^{ - t} dt How does it explain the Force? Thanks
  33. B

    Coincidence summing in gamma ray spectrometry

    In gamma-ray spectrometry with germanium detector, the summing effects have to be taken into account at low source detector distance. The peaks due to coincidence summing of X+X, X+gamma, gamma+gamma rays can complicate the spectrum obtained by this type of detector and significantly change the...
  34. E

    Derivation of Gamma: Is it Correct?

    \gamma = csc(cos^{-1}(v/c)) \gamma^{-1} = sin(cos^{-1}(v/c)) Is there something wrong with this derivation? If not, why isn't this the more formal way of writing it, it seems a lot more simple?
  35. M

    What is the significance of measuring attenuation in gamma rays?

    Hello everybody, actually yesterday i read about an experiment "ATTENUATION OF GAMMA RAYS". can anybody tell me what is meanning of word ATTENUATION.And why we are measuring it? i.e. what is the sigificance of measuring it?
  36. A

    Majorana representation of Gamma matrices.

    It is well known that at times we do need explicit representations for the Dirac gamma matrices while doing calculations with fermions. Recently I found two different expressions for Majorana representation for the gamma matrices. In one paper, the form used is: \gamma_{0} = \left(...
  37. C

    Atmospheric Gamma Ray Interactions

    Hi, Atmospheric gamma-ray extensive air showers are induced by pair-production interactions. The equation that governs pair production is: \gamma + \gamma = e^- + e^+ My understanding of the interaction is that a gamma passes "close" to the electric field of a nucleus. The nucleus acts...
  38. M

    Simplifying Gamma(xy) Expression - Help Appreciated

    what is the simplification of the following expression (in terms of gamma and\or other functions) ? \Gamma(xy) i tried the following : \Gamma(xy)=\int^{\infty}_{0} t^{xy-1} e^{-t} dt now let t^x = s => ( after some manipulation ) \Gamma(xy)=\frac{1}{x}\int^{\infty}_{0} s^{y-1}...
  39. M

    How Do You Solve Gamma Functions Like \Gamma(5/4)?

    I'am not sure how to solve this gamma function \Gamma(5/4). any help ? sorry if this is in the wrong section.
  40. M

    Why is non-collinear momentum not considered in this analysis?

    Homework Statement A Gamma photon is used in order to dissociate deuterium into a proton and neutron. the binding energy is 2.22Mev anf the rest energies for the proton and neutron are 938Mev and 939Mev respectively. determine the minmum photon energy to achieve this. consider two cases: 1-...
  41. P

    What are the Unanswered Questions About Gamma Ray Particles?

    questions about life of gamma ray particle question-are gamma ray particles unchanged after gamma ray burst 13 billion years ago? question-are changes detected not due to travel through normal space, scattering? changes due to dark matter/energy? question-positronium decay at end universe...
  42. C

    Atomic X and Gamma Rays: Physical Process

    What is the physical process common to both the emissions of atomic x rays and nuclear gamma rays? is it photoelectric.. or the inverse.
  43. N

    Regularized Upper Incomplete Gamma Functions

    Does anyone know of any properties in relation to adding two upper incomplete regularized gamma functions? i.e. can you write Q(a,z1) - Q(a,z2) = Q(a,X) ? where X(z1,z2) Extra information: a is a positive half-integer. Natski
  44. A

    Is Y Gamma-Distributed If Y = 1 + X Where X ~ Gamma(k, θ)?

    I hav a random variable X which is gamma-distributed with scale θ and shape k, i-e X ~ gamma(k,θ); Now I have another variable, Y= 1+X, is Y gamma-ditributed? if yes what will be the scale and shape parametrs for Y, and what will be the expression for the probability density function of Y...
  45. K

    Gamma Distribution (Statistics)

    A random variable X is gamma distributed with a=3, b=2 (alpha/beta). Determine the probability that 1\leqX\leq2 The first thing I did was plug a & b into the gamma distribution formula 1/(b^a \Gammaa * x^(a-1) * e^(-x/b) Which I ended up with 1/16(x^2 * e^(-x/2) Which I then though...
  46. D

    What is the Cross Section Formula for Gamma+Gamma Interaction

    Hi guys, Could someone show me how can I evaluate/measure the cross section of gamma+gamma --> electron + positron I'll be thankful for your help
  47. H

    What is the energy comparison between a gamma ray burst and vaporizing the sun?

    Homework Statement a) A back-of-the-envelope calculation shows that in about 120 seconds the gamma ray burst released a total energy of about 10^48 Joule. How does this compare to the total energy that would be released by instantly vaporizing our sun into pure energy? (The sun's mass is...
  48. B

    Calculating Width of SM Higgs Two-Photon Channel

    Hello! I would like to know how to calculate the width of the two-photon channel of the SM Higgs. It seems to be quite a tedious calculation with a dimensional regularization to perform. There are two one-loop contributions (leptons and W). Thank you very much in advance for your help! B...
  49. M

    Exploring Gamma Radiation in the Nucleus

    [SOLVED] Gamma radiation gamma radiation does anyone know how it is produced within the nucleus? and I know that gamma radiation takes place after a isotope has undergone a decay and is in an excited state. I know that what interest me is the very nature of the excited state! and how the...
  50. montoyas7940

    Simplify the following formula with Gamma functions

    \frac{\beta^\alpha \Gamma(\alpha + 1)}{\Gamma (\alpha) \beta^{\alpha+ 1}} = \frac{\alpha \Gamma (\alpha)}{ \beta \Gamma (\alpha)} = \frac{\alpha}{ \beta} This is the solution. In trying to get the middle expression out of the first I quickly end up with a mess. How should I approach this?
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