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Resonance scan

  1. Mar 18, 2014 #1
    what is breit wigner distribution function ?
    it is used in resonance scan means it decides the no of events for any specific channel. i am also giving the link of the paper where i found this

    please help me out

    thank you
    Last edited by a moderator: Mar 19, 2014
  2. jcsd
  3. Mar 19, 2014 #2
    The Breit-Wigner distribution is a particular factor appearing in the expression for the scattering cross section when this scattering happens via an intermediate particle. Consider for example the scattering [itex]a+b\to A\to X+Y[/itex]. The expression for the cross section is given by:
    \frac{d\sigma(a+b\to X+Y)}{d\vec pd s_X}=\frac{d\Gamma(A\to X)}{\Gamma(A\to all)}\frac{d\sigma(a+b\to A+Y)}{d\vec pd s_A} W(s_A)\sqrt{\frac{\vec p^2+m_A^2}{\vec p^2+s_A}},
    where the Breit-Wigner distribution is given by:
    As you can see, such a distribution gives an enhancement of the cross section (i.e. of the number of particles produced) when [itex]s_A\simeq m_A^2[/itex], provided that the width [itex]\Gamma[/itex] of the intermediate particle is not too large.
    Last edited: Mar 19, 2014
  4. Mar 19, 2014 #3
    thank you very much
    i will try to understand this and also try to correlate with the paper and will come back to you soon.

    thank you
  5. Mar 19, 2014 #4
    The paper itself is about the exotic hadron X(3872). It is a perfect example of resonance. Namely it doesn't appear as a final state of the reaction but as an intermediate particle. It is, for example, produced ad LHC via the reaction: p+p -> X(3872) -> D0 + antiD0*. As you can see this is exactly as the reaction I showed you before.
  6. Apr 3, 2014 #5
    thank you very much.

    can you please suggest me the reference book to study this ? actually I understood the things but still I want to understand in more detail.

    thank you

    Nakul Soni
    Last edited: Apr 3, 2014
  7. Apr 3, 2014 #6
    Do you mean the X(3872) or resonances in general?
  8. Apr 3, 2014 #7
    for the basic of Breit-Wigner and the distribution function.
  9. Apr 3, 2014 #8
    One of the best books is De Wit - Field theory in particle physics. In particular the chapter on decay rates
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