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Resonance scan 
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#1
Mar1814, 12:40 PM

P: 13

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 http://pos.sissa.it/archive/conferen...io2012_018.pdf please help me out thank you 


#2
Mar1914, 10:14 AM

P: 323

The BreitWigner 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 BreitWigner distribution is given by: $$ W(s_A)=\frac{1}{\pi}\frac{m_A\Gamma}{(s_Am_A^2)^2+m_A^2\Gamma^2}. $$ 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. 


#3
Mar1914, 11:27 AM

P: 13

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 


#4
Mar1914, 11:38 AM

P: 323

Resonance scan
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.



#5
Apr314, 12:42 AM

P: 13

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 


#6
Apr314, 07:22 AM

P: 323

Do you mean the X(3872) or resonances in general?



#7
Apr314, 07:30 AM

P: 13

for the basic of BreitWigner and the distribution function.



#8
Apr314, 07:58 AM

P: 323

One of the best books is De Wit  Field theory in particle physics. In particular the chapter on decay rates



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