TY - JOUR

T1 - Z -boson decays to a vector quarkonium plus a photon

AU - Bodwin, Geoffrey T.

AU - Chung, Hee Sok

AU - Ee, June Haak

AU - Lee, Jungil

N1 - Funding Information:
We thank Deshan Yang for clarifying several issues with regard to the formulas in Ref. [14] . We also thank Matthias Neubert and Matthias König for a helpful discussion. The work of G. T. B. is supported by the U.S. Department of Energy, Division of High Energy Physics, under Contract No. DE-AC02-06CH11357. The work of H. S. C. at CERN is supported by the Korean Research Foundation (KRF) through the CERN-Korea fellowship program. The work of J.-H. E. and J. L. was supported by the National Research Foundation of Korea (NRF) under Contract No. NRF-2017R1E1A1A01074699. The submitted manuscript has been created in part by UChicago Argonne, LLC, Operator of Argonne National Laboratory. Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - We compute the decay rates for the processes Z→V+γ, where Z is the Z-boson, γ is the photon, and V is one of the vector quarkonia J/ψ or (nS), with n=1, 2, or 3. Our computations include corrections through relative orders αs and v2 and resummations of logarithms of mZ2/mQ2, to all orders in αs, at next-to-leading-logarithmic accuracy. (v is the velocity of the heavy quark Q or the heavy antiquark Q̄ in the quarkonium rest frame, and mZ and mQ are the masses of Z and Q, respectively.) Our calculations are the first to include both the order-αs correction to the light-cone distributions amplitude and the resummation of logarithms of mZ2/mQ2 and are the first calculations for the (2S) and (3S) final states. The resummations of logarithms of mZ2/mQ2 that are associated with the order-αs and order-v2 corrections are carried out by making use of the Abel-Padé method. We confirm the analytic result for the order-v2 correction that was presented in a previous publication, and we correct the relative sign of the direct and indirect amplitudes and some choices of scales in that publication. Our branching fractions for Z→J/ψ+γ and Z→(1S)+γ differ by 2.0σ and -4.0σ, respectively, from the branching fractions that are given in the most recent publication on this topic (in units of the uncertainties that are given in that publication). However, we argue that the uncertainties in the rates are underestimated in that publication.

AB - We compute the decay rates for the processes Z→V+γ, where Z is the Z-boson, γ is the photon, and V is one of the vector quarkonia J/ψ or (nS), with n=1, 2, or 3. Our computations include corrections through relative orders αs and v2 and resummations of logarithms of mZ2/mQ2, to all orders in αs, at next-to-leading-logarithmic accuracy. (v is the velocity of the heavy quark Q or the heavy antiquark Q̄ in the quarkonium rest frame, and mZ and mQ are the masses of Z and Q, respectively.) Our calculations are the first to include both the order-αs correction to the light-cone distributions amplitude and the resummation of logarithms of mZ2/mQ2 and are the first calculations for the (2S) and (3S) final states. The resummations of logarithms of mZ2/mQ2 that are associated with the order-αs and order-v2 corrections are carried out by making use of the Abel-Padé method. We confirm the analytic result for the order-v2 correction that was presented in a previous publication, and we correct the relative sign of the direct and indirect amplitudes and some choices of scales in that publication. Our branching fractions for Z→J/ψ+γ and Z→(1S)+γ differ by 2.0σ and -4.0σ, respectively, from the branching fractions that are given in the most recent publication on this topic (in units of the uncertainties that are given in that publication). However, we argue that the uncertainties in the rates are underestimated in that publication.

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U2 - 10.1103/PhysRevD.97.016009

DO - 10.1103/PhysRevD.97.016009

M3 - Article

AN - SCOPUS:85041750042

VL - 97

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 1

M1 - 016009

ER -