Width Difference in the B-B¯ System at Next-to-Next-to-Leading Order of QCD

May 16, 2022
7 pages
Published in:
  • Phys.Rev.Lett. 129 (2022) 10, 102001
  • Published: Aug 31, 2022
e-Print:
Report number:
  • TTP22-030,
  • P3H-22-051

Citations per year

201120142017202020231048
Abstract: (APS)
We extend the theoretical prediction for the width difference ΔΓq in the mixing of neutral B mesons in the Standard Model to next-to-next-to-leading order in αs. To this aim, we calculate three-loop diagrams with two |ΔB|=1 current-current operators analytically. In the matching between |ΔB|=1 and |ΔB|=2 effective theories, we regularize the infrared divergences dimensionally and take into account all relevant evanescent operators. Further elements of the calculation are the two-loop renormalization matrix Zij for the |ΔB|=2 operators and the O(αs2) corrections to the finite renormalization that ensures the 1/mb suppression of the operator R0 at two-loop order. Our theoretical prediction reads ΔΓs/ΔMs=(4.33±0.93)×10-3 if expressed in terms of the bottom mass in the MS¯ scheme and ΔΓs/ΔMs=(4.20±0.95)×10-3 for the use of the potential-subtracted mass. While the controversy on |Vcb| affects both ΔΓs and ΔMs, the ratio ΔΓs/ΔMs is not affected by the uncertainty in |Vcb|.
Note:
  • 7 pages, 4 figures
  • width: difference
  • higher-order: 2
  • infrared problem: regularization
  • renormalization: finite
  • operator: suppression
  • bottom: mass
  • mixing
  • B anti-B
  • quantum chromodynamics