2015/05/31 by Matthias König, Matthias Koenig, Matthias Neubert · 1 citation
Physics and Astronomy · #Algorithm #Amplitude #Factorization #Higgs boson #High-Energy Particle Collisions Research #Meson #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #Yukawa potential #hep-ph
paper · pdf · doi:10.1007/jhep08(2015)012
published as JHEP 1508 (2015) 012 · 25 pages plus appendices, 9 figures, 5 tables; v2: NLO evolution of Gegenbauer moments implemented in Appendix B, some references added; v3: typo in the value of C_{γZ}(0) after eq. (35) fixed
openalex publication_date 2015/08/01 · arxiv created 2016/03/29 · arxiv updated 2016/03/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A bstract We present a detailed analysis of the rare exclusive Higgs boson decays into a single vector meson and a photon and investigate the possibility of using these processes to probe the light-quark Yukawa couplings. We work with an effective Lagrangian with modified Higgs couplings to account for possible new-physics effects in a model-independent way. The h → Vγ decay rate is governed by the destructive interference of two amplitudes, one of which involves the Higgs coupling to the quark anti-quark pair inside the vector meson. We derive this amplitude at next-to-leading order in α s using QCD factorization, including the resummation of large logarithmic corrections and accounting for the effects of flavor mixing. The high factorization scale μ ∼ m h ensures that our results are rather insensitive to the hadronic parameters characterizing the light-cone distribution amplitude of the vector meson. The second amplitude arises from the loop-induced effective hγγ * and hγZ * couplings, where the off-shell gauge boson converts into the vector meson. We devise a strategy to eliminate theoretical uncertainties related to this amplitude to almost arbitrary precision. This opens up the possibility to probe for O(1) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:mn>1</mml:mn> </mml:mfenced> </mml:math> modifications of the c - and b -quark Yukawa couplings and O(30) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> <mml:mfenced> <mml:mn>30</mml:mn> </mml:mfenced> </mml:math> modifications of the s -quark Yukawa coupling in the high-luminosity LHC run. In particular, we show that measurements of the ratios Br( h → Υ( nS ) γ )/Br( h → γγ ) and Br(h→ bb)/Br(h→ γ γ ) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> <mml:mi>r</mml:mi> <mml:mfenced> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>→</mml:mo> <mml:mi>b</mml:mi> <mml:mover> <mml:mi>b</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:mfenced> <mml:mo>/</mml:mo> <mml:mi>B</mml:mi> <mml:mi>r</mml:mi> <mml:mfenced> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>→</mml:mo> <mml:mi>γ</mml:mi> <mml:mi>γ</mml:mi> </mml:mrow> </mml:mfenced> </mml:math> can provide complementary information on the real and imaginary parts of the b -quark Yukawa coupling. More accurate measurements would be possible at a future 100 TeV proton-proton collider.