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Title: Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma

Abstract

Radiative decays of the B meson, B {yields} X{sub s}{gamma}, proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B {yields} X{sub s}{gamma} decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as e{sup +}e{sup -} annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 {+-} 0.16) GeV/c{sup 2}; {mu}{submore » {pi}}{sup 2} = (0.65 {+-} 0.29) GeV{sup 2}. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter |V{sub ub}|. Based on these parameters and heavy quark expansion, the full branching fraction is obtained as: {Beta}(B {yields} X{sub s}{gamma}){sup E{sub {gamma}}>1.6 GeV} = (4.05 {+-} 0.32(stat) {+-} 0.38(syst) {+-} 0.29(model)) x 10{sup -4}. This result is in good agreement with previous measurements, the statistical and systematic errors are comparable. It is also in good agreement with the theoretical Standard Model predictions, and thus within the present errors there is no indication of any interactions not accounted for in the Standard Model. This finding implies strong constraints on physics beyond the Standard Model.« less

Authors:
;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
877983
Report Number(s):
SLAC-R-795
TRN: US0601774
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANNIHILATION; B MESONS; B QUARKS; BOUND STATE; DECAY; KINETICS; LEPTONS; MESONS; NEUTRAL CURRENTS; PHOTONS; PHYSICS; QUANTUM CHROMODYNAMICS; QUARKS; RADIATIVE DECAY; STANDARD MODEL; T QUARKS; WEAK INTERACTIONS; Experiment-HEP,HEPEX, HEPPH

Citation Formats

Ozcan, V.E., and /SLAC /Stanford U., Appl. Phys. Dept. Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma. United States: N. p., 2006. Web. doi:10.2172/877983.
Ozcan, V.E., & /SLAC /Stanford U., Appl. Phys. Dept. Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma. United States. doi:10.2172/877983.
Ozcan, V.E., and /SLAC /Stanford U., Appl. Phys. Dept. Fri . "Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma". United States. doi:10.2172/877983. https://www.osti.gov/servlets/purl/877983.
@article{osti_877983,
title = {Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma},
author = {Ozcan, V.E. and /SLAC /Stanford U., Appl. Phys. Dept.},
abstractNote = {Radiative decays of the B meson, B {yields} X{sub s}{gamma}, proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B {yields} X{sub s}{gamma} decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as e{sup +}e{sup -} annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 {+-} 0.16) GeV/c{sup 2}; {mu}{sub {pi}}{sup 2} = (0.65 {+-} 0.29) GeV{sup 2}. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter |V{sub ub}|. Based on these parameters and heavy quark expansion, the full branching fraction is obtained as: {Beta}(B {yields} X{sub s}{gamma}){sup E{sub {gamma}}>1.6 GeV} = (4.05 {+-} 0.32(stat) {+-} 0.38(syst) {+-} 0.29(model)) x 10{sup -4}. This result is in good agreement with previous measurements, the statistical and systematic errors are comparable. It is also in good agreement with the theoretical Standard Model predictions, and thus within the present errors there is no indication of any interactions not accounted for in the Standard Model. This finding implies strong constraints on physics beyond the Standard Model.},
doi = {10.2172/877983},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2006},
month = {1}
}

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