Measurement of the Branching Fraction and Photon Energy Moments of B to Xs gamma and A_cp (B to X_{s+d} gamma)

Journal Article · Tue Sep 26 00:00:00 EDT 2006 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.97.171803· OSTI ID:892633

Aubert, B

The photon spectrum in B {yields} X{sub s}{gamma} decay, where X{sub s} is any strange hadronic state, is studied using a data sample of 88.5 x 10{sup 6} e{sup +}e{sup -} {yields} {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR experiment at SLAC. The partial branching fraction, {Delta}{Beta}(B {yields} X{sub s}{gamma}) = (3.67 {+-} 0.29(stat.) {+-} 0.34(sys.) {+-} 0.29(model)) x 10{sup -4}, the first moment <E{sub {gamma}}> = 2.288 {+-} 0.025 {+-} 0.017 {+-} 0.015 GeV and the second moment <E{sub {gamma}}{sup 2}> = 0.0328 {+-} 0.0040 {+-} 0.0023 {+-} 0.0036 GeV{sup 2} are measured for the photon energy range 1.9 GeV < E{sub {gamma}} < 2.7 GeV. They are also measured for narrower E{sub {gamma}} ranges. The moments are then fit to recent theoretical calculations to extract the Heavy Quark Expansion parameters, m{sub b} and {mu}{sub {pi}}{sup 2}, and to extrapolate the partial branching fraction to E{sub {gamma}} > 1.6 GeV. In addition, the direct CP asymmetry A{sub CP}(B {yields} X{sub s+d{gamma}}) is measured to be -0.110 {+-} 0.115(stat.) {+-} 0.017(sys.).

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 892633
• Report Number(s): SLAC-PUB-12002; hep-ex/0607071
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters
• Country of Publication: United States
• Language: English

Related Subjects

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STANFORD LINEAR ACCELERATOR CENTER