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Title: Measurement of alpha / phi_2 from B to pi pi Decays

Abstract

The current results on B {yields} {pi}{pi} decays and SU(2) constraints on the Unitarity Triangle angle {alpha} or {phi}{sub 2} from the B-factories are summarized. Based on these measurements, predictions of the isospin analysis constraints at the end of the lifetime of both B-factories are given.

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
897728
Report Number(s):
SLAC-PUB-12298
hep-ex/0701031; TRN: US0701503
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: Contributed to 4th International Workshop on the CKM Unitarity Triangle (CKM 2006), Nagoya, Japan, 12-16 Dec 2006
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ISOSPIN; LIFETIME; UNITARITY; Experiment-HEP,HEPEX

Citation Formats

Bevan, A.J.. Measurement of alpha / phi_2 from B to pi pi Decays. United States: N. p., 2007. Web.
Bevan, A.J.. Measurement of alpha / phi_2 from B to pi pi Decays. United States.
Bevan, A.J.. Wed . "Measurement of alpha / phi_2 from B to pi pi Decays". United States. doi:. https://www.osti.gov/servlets/purl/897728.
@article{osti_897728,
title = {Measurement of alpha / phi_2 from B to pi pi Decays},
author = {Bevan, A.J.},
abstractNote = {The current results on B {yields} {pi}{pi} decays and SU(2) constraints on the Unitarity Triangle angle {alpha} or {phi}{sub 2} from the B-factories are summarized. Based on these measurements, predictions of the isospin analysis constraints at the end of the lifetime of both B-factories are given.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 17 00:00:00 EST 2007},
month = {Wed Jan 17 00:00:00 EST 2007}
}

Conference:
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  • We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K{sub 1}(1270) or K{sub 1}(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454x10{sup 6} BB pairs produced in e{sup +}e{sup -} annihilation. We measure the branching fractions B(B{sup 0{yields}}K{sub 1}(1270){sup +{pi}-}+K{sub 1}(1400){sup +{pi}-})=3.1{sub -0.7}{sup +0.8}x10{sup -5} and B(B{sup +{yields}}K{sub 1}(1270){sup 0{pi}+}+K{sub 1}(1400){sup 0{pi}+})=2.9{sub -1.7}{sup +2.9}x10{sup -5} (<8.2x10{sup -5} at 90% confidence level), where the errors are statistical and systematic combined. The B{sup 0} decay mode is observed withmore » a significance of 7.5{sigma}, while a significance of 3.2{sigma} is obtained for the B{sup +} decay mode. Based on these results, we estimate the weak phase {alpha}=(79{+-}7{+-}11) deg. from the time-dependent CP asymmetries in B{sup 0{yields}}a{sub 1}(1260){sup {+-}{pi}{+-}}decays.« less
  • We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K{sub 1}(1270) or K{sub 1}(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. We measure the branching fractions {Beta}(B{sup 0} {yields} K{sub 1}(1270){sup +}{pi}{sup -} + K{sub 1}(1400){sup +}{pi}{sup -}) = 3.1{sub 0.7}{sup +0.8} x 10{sup -5} and {Beta}(B{sup +} {yields} K{sub 1}(1270){sup 0}{pi}{sup +} + K{sub 1}(1400){sup 0}{pi}{sup +}) = 2.9{sub -1.7}{sup +2.9} x 10{sup -5} (<more » 8.2 x 10{sup -5} at 90% confidence level), where the errors are statistical and systematic combined. The B{sup 0} decay mode is observed with a significance of 7.5{sigma}, while a significance of 3.2{sigma} is obtained for the B{sup +} decay mode. Based on these results, we estimate the weak phase {alpha} = (79 {+-} 7 {+-} 11){sup o} from the time dependent CP asymmetries in B{sup 0} {yields} a{sub 1}(1260){sup {+-}}{pi}{sup {-+}} decays.« less
  • The authors present preliminary results of improved measurements of the CP-violating asymmetries and branching fractions in the decays B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} K{sup +}{pi}{sup -}, B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and B{sup 0} {yields} K{sup 0}{pi}{sup 0}. This update includes all data taken at the {Upsilon}(4S) resonance by the BABAR experiment at the asymmetric PEP-II B-meson factory at SLAC, corresponding to 467 {+-} 5 million B{bar B} pairs. They find S{sub {pi}{pi}} = -0.68 {+-} 0.10 {+-} 0.03, C{sub {pi}{pi}} = -0.25 {+-} 0.08 {+-} 0.02, {Alpha}{sub K{sub {pi}}} = -0.107 {+-} 0.016{sub -0.004},{supmore » +0.006}, C{sub {pi}{sup 0}{pi}{sup 0}} = -0.43 {+-} 0.26 {+-} 0.05, {Beta}(B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}) = (1.83 {+-} 0.21 {+-} 0.13) x 10{sup -6}, {Beta}(B{sup 0} {yields} K{sup 0}{pi}{sup 0}) = (10.1 {+-} 0.6 {+-} 0.4) x 10{sup -6}, where the first error is statistical and the second is systematic. They observe CP violation with a significance of 6.7{sigma} in B{sup 0} {yields} {pi}{sup -} and 6.1{sigma} in B{sup 0} {yields} K{sup +}{pi}{sup -}. Constraints on the Unitarity Triangle angle {alpha} are determined from the isospin relation between all B {yields} {pi}{pi} rates and asymmetries.« less
  • The authors present preliminary measurements of the Cp asymmetries and branching fractions for B {yields} {pi}{pi} and B {yields} K{pi} decays. A total of 347 million B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC are used for these results.