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Setting Limits on Supersymmetry Using Simplified Models
07:46

Setting Limits on Supersymmetry Using Simplified Models

Published on: November 16, 2013

Experimental limits on weak annihilation contributions to decays.

J L Rosner1, N E Adam, J P Alexander

  • 1Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA.

Physical Review Letters
|April 12, 2006
PubMed
Summary

This study sets the first experimental limits on weak annihilation contributions to B meson decays, finding them to be less than 7.4%. This result helps refine measurements of the CKM matrix element Vub.

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Area of Science:

  • High Energy Physics
  • Particle Physics
  • Quantum Chromodynamics

Background:

  • Semileptonic B meson decays are crucial for determining the CKM matrix element |Vub|.
  • Inclusive measurements of B --> Xulnu decays are sensitive to theoretical uncertainties, including weak annihilation contributions.
  • Weak annihilation (WA) is a non-perturbative process that can affect theoretical predictions.

Purpose of the Study:

  • To establish the first experimental constraints on high-q^2 contributions from the weak annihilation (WA) decay mechanism in charmless semileptonic B decays.
  • To quantify the potential bias introduced by WA contributions on |Vub| determinations from inclusive B --> Xulnu measurements.
  • To assess the impact of these WA contributions on previous inclusive |Vub| measurements.

Main Methods:

  • Experimental measurement of charmless semileptonic B decays.
  • Analysis of high-momentum transfer (high-q^2) contributions.
  • Utilizing a variety of theoretical models and available theoretical input.
  • Setting confidence limits on the WA fraction (Gamma_WA / Gamma_B-->Xuar{\nu}).

Main Results:

  • The first experimental limits on high-q^2 WA contributions to charmless semileptonic B decays are presented.
  • A limit of Gamma_WA / Gamma_B-->Xuar{\nu} < 7.4% at 90% confidence level was established.
  • The potential impact of WA contributions on inclusive |Vub| determinations was assessed.

Conclusions:

  • Experimental constraints on weak annihilation contributions are now available.
  • These limits provide crucial information for improving the accuracy of |Vub| measurements.
  • The study highlights the importance of accounting for non-perturbative effects in B physics.