B¯c→ηc, B¯c→J/ψ and B¯→D(*) semileptonic decays including new physics

2020/07/31 by Neus Penalva, N. Penalva, E. Hernández +1 · 11 citations
Physics and Astronomy · #Electron #Hadron #Lambda #Lepton #Meson #Neutrino Physics Research #Nuclear physics #Observable #Omega #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Semileptonic decay #hep-ex #hep-ph

paper · pdf · doi:10.1103/physrevd.102.096016

published in Physical review. D/Physical review. D. 102(9) (American Physical Society) · 28 latex pages, 26 figures, 2 tables, a new reference added and a few misprints corrected

openalex created_date 2020/07/29 · arxiv created 2020/11/05 · openalex publication_date 2020/11/12 · arxiv updated 2020/11/18 · openalex updated_date 2026/08/05

Abstract

We apply the general formalism derived by Penalva et al. [Phys. Rev. D 101, 113004 (2020)] to the semileptonic decay of pseudoscalar mesons containing a b quark. While present B\ensuremath→D^(*) data give the strongest evidence in favor of lepton flavor universality violation, the observables that are normally considered are not able to distinguish between different new physics (NP) scenarios. In the above reference we discussed the relevant role that the various contributions to the double differential decay widths d²\mathrm\ensuremathΓ/(d\ensuremathωdcos\ensuremathθ_\ensuremathℓ) and d²\mathrm\ensuremathΓ/(d\ensuremathωdE_\ensuremathℓ) could play to this end. Here \ensuremathω is the product of the two hadron four-velocities, \ensuremathθ_\ensuremathℓ is the angle made by the final lepton and final hadron three-momenta in the center of mass of the final two-lepton system, and E_\ensuremathℓ is the final charged lepton energy in the laboratory system. The formalism was applied by Penalva et al. to the analysis of the \mathrm\ensuremathΛ_b\ensuremath→\mathrm\ensuremathΛ_c semileptonic decay, showing the new observables were able to tell apart different NP scenarios. Here we analyze the B_c\ensuremath→\ensuremathη_c\ensuremathτ\ensuremathν_\ensuremathτ, B_c\ensuremath→J/\ensuremathψ\ensuremathτ\ensuremathν_\ensuremathτ, B\ensuremath→D\ensuremathτ\ensuremathν_\ensuremathτ and B\ensuremath→D^*\ensuremathτ\ensuremathν_\ensuremathτ semileptonic decays. We find that, as a general rule, the B_c\ensuremath→J/\ensuremathψ observables, even including \ensuremathτ polarization, are less optimal for distinguishing between NP scenarios than those obtained from B_c\ensuremath→\ensuremathη_c decays, or those presented by Penalva et al. for the related \mathrm\ensuremathΛ_b\ensuremath→\mathrm\ensuremathΛ_c semileptonic decay. Finally, we show that B\ensuremath→D and B_c\ensuremath→\ensuremathη_c, and B\ensuremath→D^* and B_c\ensuremath→J/\ensuremathψ decay observables exhibit similar behaviors.

Citations

• Diagnosing new physics inb→cτντdecays in the light of the recentBABARresult
• Update of|Vcb|from theB¯→D*ℓν¯form factor at zero recoil with three-flavor lattice QCD
• Semileptonic Bc decay and heavy quark spin symmetry
• Study of exclusive semileptonic and nonleptonic decays ofBc−in a nonrelativistic quark model
• Evidence for an Excess ofB¯→D(*)τ−ν¯τDecays
• R(D∗), |Vcb|, and the Heavy Quark Symmetry relations between form factors
• Model-independent investigation of the RJ/ψ,ηc and ratios of decay widths of semileptonic Bc decays into a P-wave charmonium
• Solutions to R-RD⁎ in light of Belle 2019 data
• A measurable angular distribution for B→ D^∗ τ^-v_τ decays