Right-Handed Currents in B Decay Revisited

Abstract

We critically re-examine the case for and against a sizeable right-handed component in the $b\to c$ charged current coupling with a strength $\xi$ relative to the conventional left-handed current. Using data from CLEO on the decay $B\to D^{\ast }\ell \nu$, as well as our knowledge of $V_{cb}$ extracted from both inclusive and exclusive processes, we are able to determine the presently allowed parameter space for $\xi$ via HQET. We then identify several observables which could be measured at $B$ factories to either strengthen these constraints or otherwise observe right-handed currents. This parameter space region is found to be consistent with the low degree of ${\Lambda }_b$ polarization as determined by ALEPH as well as the measurements of the charged lepton and neutrino energy spectra from $b$ decay made by L3. We discuss how future measurements of semileptonic decay distributions may distinguish between exotic ${\Lambda }_b$ depolarization mechanisms and the existence of right-handed currents. Within the parameter space allowed by CLEO, using the Left-Right Symmetric Model as a guide, we perform a detailed search for specific sub-regions which can lead to a reduction in both the $B$ semileptonic branching fraction as well as the the average yield of charmed quarks in $B$ decay. The results provide a concrete realization of an earlier suggestion by Voloshin but may lead to potential difficulties with certain penguin mediated decay processes.

52 pages, 8 figs, LaTex, typos corrected, references added, slight augmentation of discussion

References in corpus (7)

• Search for New Particles Decaying to Dijets at CDF
• Penguin Diagrams, Charmless B-Decays and the ``Missing Charm Puzzle''
• Polarization Measurements and T-Violation in Exclusive Semileptonic B Decays
• Bound on V+A admixture in the b -> c current from inclusive vs. exclusive semileptonic decays of B mesons
• Measurement of the $\bar{B}\to D\ell \bar{\nu }$ Partila Width and Form Factor Parameters
• Symmetry Tests of the Electroweak Interaction from Muon Capture on 3He
• Right-Handed b to c and u Coupling Model and CP Violation

Cited by in corpus (10)

• Probing for New Physics in Polarized ${\Lambda }_b$ decays at the Z
• Looking for Novel CP-Violating Effects in B->K^*l^+l^-
• Measurement of the Average Polarization of b Baryons in Hadronic Z^0 Decays
• Lepton angular asymmetries in semileptonic charmful B decays
• Complete Michel Parameter Analysis of inclusive semileptonic b \to c transition
• CP Violation and Family Mixing in the Effective Electroweak Lagrangian
• Implications of the anomalous top quark couplings in $B_s-{\bar{B}}_s$ mixing, $B\to X_s\gamma$ and top quark decays
• Testing quark mass matrices with right-handed mixings
• Fast CP Violation
• Testing the chirality of b to u current with B^0 \to ρ^ - \ell^+ ν