
#1
Jan114, 02:22 AM

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We say onshell and offshell mass of quarks. 1) What is the difference onshell and offshell mass of quarks. 2) At lab. center of mass frame for lepton particles p^{2}= m^{2}. Can we apply this equation for quarks.
Thank you! 



#2
Jan114, 04:14 AM

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Hi Hluf!
a quark never has offshell mass offshell mass is a mathematical trick which helps in the calculations for Feynman diagrams yes this applies to everything (and in any frame): leptons hadrons and photons you can regard it as the definition of m (the mass) 



#3
Jan114, 05:55 AM

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#4
Jan114, 06:00 AM

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Relation between momentum and mass of quarks 



#5
Jan114, 10:08 AM

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Quarks can appear as intermediate particles in Feynman diagrams, where they are 'offshell'. 



#6
Jan114, 05:11 PM

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#7
Jan114, 05:39 PM

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#8
Jan114, 06:54 PM

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Yes, some people will make this argument. Some people find quibbling entertaining. It's not a very good argument for promoting understanding of QFT to people new to it, though.
There really is a difference between real and virtual, and to quote Potter Stewart, "I know it when I see it" 


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