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Title: Method for Extracting the Quark Mixing Parameter cos{alpha} via B{sup {+-}} {yields}{pi}{sup {+-}}e{sup +}e{sup -}

Abstract

We show that it is possible to extract the weak mixing angle {alpha} via a measurement of the rate for B{sup {+-}}{yields}{pi}{sup {+-}}e{sup +} e{sup -} . The sensitivity to cos {alpha} results from the interference between the long and short distance contributions. The short distance contribution is given in terms of semileptonic form factors. The long distance contribution can be calculated using Ward identities and a short distance operator product expansion if the invariant mass of the lepton pair, q{sup 2} , is larger than {lambda}{sup 2}{sub QCD} . For q{sup 2}{>=}2 GeV {sup 2} the branching fraction is approximately 1x10{sup -8}|V{sub td}/0.008|{sup 2} . The shape of d{gamma}/dq{sup 2} is very sensitive to the value of cos {alpha} at small values of q{sup 2} and varies by 50% when -1<cos {alpha}<1 at q{sup 2}=2 GeV {sup 2} . (c) 2000 The American Physical Society.

Authors:
 [1];  [1];  [2]
  1. Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)
  2. Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
Publication Date:
OSTI Identifier:
20216585
Resource Type:
Journal Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 84; Journal Issue: 20; Other Information: PBD: 15 May 2000; Journal ID: ISSN 0031-9007
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; B MINUS MESONS; B PLUS MESONS; PIONS PLUS; PIONS MINUS; ELECTRONS; POSITRONS; PARTICLE DECAY; CP INVARIANCE; FORM FACTORS; WARD IDENTITY; BRANCHING RATIO; QUARKS; THEORETICAL DATA

Citation Formats

Grinstein, Benjamin, Nolte, Detlef R., and Rothstein, Ira Z. Method for Extracting the Quark Mixing Parameter cos{alpha} via B{sup {+-}} {yields}{pi}{sup {+-}}e{sup +}e{sup -}. United States: N. p., 2000. Web. doi:10.1103/PhysRevLett.84.4545.
Grinstein, Benjamin, Nolte, Detlef R., & Rothstein, Ira Z. Method for Extracting the Quark Mixing Parameter cos{alpha} via B{sup {+-}} {yields}{pi}{sup {+-}}e{sup +}e{sup -}. United States. doi:10.1103/PhysRevLett.84.4545.
Grinstein, Benjamin, Nolte, Detlef R., and Rothstein, Ira Z. Mon . "Method for Extracting the Quark Mixing Parameter cos{alpha} via B{sup {+-}} {yields}{pi}{sup {+-}}e{sup +}e{sup -}". United States. doi:10.1103/PhysRevLett.84.4545.
@article{osti_20216585,
title = {Method for Extracting the Quark Mixing Parameter cos{alpha} via B{sup {+-}} {yields}{pi}{sup {+-}}e{sup +}e{sup -}},
author = {Grinstein, Benjamin and Nolte, Detlef R. and Rothstein, Ira Z.},
abstractNote = {We show that it is possible to extract the weak mixing angle {alpha} via a measurement of the rate for B{sup {+-}}{yields}{pi}{sup {+-}}e{sup +} e{sup -} . The sensitivity to cos {alpha} results from the interference between the long and short distance contributions. The short distance contribution is given in terms of semileptonic form factors. The long distance contribution can be calculated using Ward identities and a short distance operator product expansion if the invariant mass of the lepton pair, q{sup 2} , is larger than {lambda}{sup 2}{sub QCD} . For q{sup 2}{>=}2 GeV {sup 2} the branching fraction is approximately 1x10{sup -8}|V{sub td}/0.008|{sup 2} . The shape of d{gamma}/dq{sup 2} is very sensitive to the value of cos {alpha} at small values of q{sup 2} and varies by 50% when -1<cos {alpha}<1 at q{sup 2}=2 GeV {sup 2} . (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevLett.84.4545},
journal = {Physical Review Letters},
issn = {0031-9007},
number = 20,
volume = 84,
place = {United States},
year = {2000},
month = {5}
}