BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Violation and Restoration of Probability Positivity in Perturbativ
 e Quantum Field Theory
DTSTART;VALUE=DATE-TIME:20261024T060000Z
DTEND;VALUE=DATE-TIME:20261024T062000Z
DTSTAMP;VALUE=DATE-TIME:20261025T015932Z
UID:indico-contribution-2999@indico.itp.ac.cn
DESCRIPTION:Speakers: Bin Gong ()\nWe address the long-standing problem of
  negative decay and production rates in perturbative QCD \nfor exclusive p
 rocesses by proposing amplitude-level NRQCD factorization as a systematic 
 prescription. \nBuilding on this\, we present the first complete next-to-n
 ext-to-leading-order (NNLO) QCD correction to \nthe decay $J/\\psi \\to 3\
 \gamma$. The resulting partial width\, \n$\\Gamma(J/\\psi \\to 3\\gamma) =
  0.96^{+4.32}_{-0.13}$ eV\, combines this NNLO contribution with \nthe kno
 wn up to $\\mathcal{O}(\\alpha_s v^2)$ relativistic correction and shows m
 arkedly improved \nagreement with the high-precision BESIII measurement. I
 n the same way\, \n$\\Gamma(\\Upsilon \\to 3\\gamma) = 0.0086^{+0.0028}_{-
 0.0006}$ eV is obtained. \n\nFrom a first-principles perspective\, it is c
 lear that for exclusive processes\, taking the complete \nmodulus squared 
 of the full amplitude is precisely the proper definition of the probabilit
 y \ndistribution and guarantees its manifest positivity. This makes the am
 plitude-level prescription \nthe natural and physically motivated scheme. 
 For inclusive processes\, however\, one is forced to \nabandon the full mo
 dulus square due to the need to cancel infrared divergences at the level o
 f \nthe truncated squared amplitude.\n\nBased on arXiv:2603.26199.\n\nhttp
 s://indico.itp.ac.cn/event/427/contributions/2999/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/2999/
END:VEVENT
END:VCALENDAR