Nonperturbative O( mc−2) effects in B→ Xsγ from heavy quark effective theory

• Published in: Physics letters. B Vol. 439; no. 1; pp. 165 - 170
• Main Author: Chay, Junegone
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 29.10.1998
• Subjects: Heavy quark effective theory; Nonperturbative effects; Operator product expansion; Heavy quark effective theory; Nonperturbative effects; Operator product expansion
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(98)01011-9

The nonperturbative contribution, suppressed by powers of the charm quark mass m c , in the inclusive decay B→ X s γ is analyzed in the context of heavy quark effective field theory (HQEFT). According to previous analyses, the leading effects of O(1/ m c 2) arise from an external gluon attached to a charm quark loop and can be expressed in terms of the chromomagnetic interaction of the b quark inside the B meson. This is also true at leading order in the HQEFT approach. However the structure of higher-dimensional operators is different because the effects of external gluons alone do not give a complete set of operators. A systematic method to derive all the high-dimensional operators can be obtained in the HQEFT scheme using the operator product expansion.