skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Nonuniversal Z{sup '} couplings in B decays

Abstract

We study the impacts of the nonuniversal Z{sup '} model, providing flavor-changing neutral current at tree level, on the branching ratios (BRs), CP asymmetries (CPAs), and polarization fractions of B decays. We find that, for satisfying the current data, the new left- and right-handed couplings have to be included at the same time. The new introduced effective interactions not only could effectively explain the puzzle of small longitudinal polarization in B{yields}K*{phi} decays, but also provide a solution to the small CPA of B{sup {+-}}{yields}{pi}{sup 0}K{sup {+-}}. We also find that the favorable CPA of B{sup {+-}}{yields}{pi}{sup 0}K{sup {+-}} is opposite in sign to the standard model; meanwhile, the CPA of B{sub d}{yields}{pi}{sup 0}K has to be smaller than -10%. In addition, by using the values of parameters which are constrained by B{yields}{pi}K, we find that the favorable ranges of BRs, CPAs, longitudinal polarizations, and perpendicular transverse polarizations for (B{sup {+-}}{yields}{rho}{sup {+-}}K*,B{sub d}{yields}{rho}{sup {+-}}K*{sup {+-}}) are (17.1{+-}3.9,10.0{+-}2.0)x10{sup -6}, (3{+-}5,21{+-}7)%, (0.66{+-}0.10,0.44{+-}0.08), and (0.14{+-}0.10,0.25{+-}0.09), respectively.

Authors:
 [1];  [2];  [3]
  1. Department of Physics, National Cheng-Kung University, Tainan 701, Taiwan (China)
  2. (China)
  3. Department of Physics, National Tsing-Hua University, Hsin-Chu 300, Taiwan (China)
Publication Date:
OSTI Identifier:
20782834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 7; Other Information: DOI: 10.1103/PhysRevD.73.075003; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; B MESONS; BRANCHING RATIO; CP INVARIANCE; HADRONIC PARTICLE DECAY; K*-892 MESONS; KAONS MINUS; KAONS PLUS; MATHEMATICAL SOLUTIONS; NEUTRAL CURRENTS; PARTICLE INTERACTIONS; PIONS NEUTRAL; POLARIZATION; STANDARD MODEL

Citation Formats

Chen, C.-H., National Center for Theoretical Sciences, Taiwan, and Hatanaka, Hisaki. Nonuniversal Z{sup '} couplings in B decays. United States: N. p., 2006. Web. doi:10.1103/PHYSREVD.73.075003.
Chen, C.-H., National Center for Theoretical Sciences, Taiwan, & Hatanaka, Hisaki. Nonuniversal Z{sup '} couplings in B decays. United States. doi:10.1103/PHYSREVD.73.075003.
Chen, C.-H., National Center for Theoretical Sciences, Taiwan, and Hatanaka, Hisaki. Sat . "Nonuniversal Z{sup '} couplings in B decays". United States. doi:10.1103/PHYSREVD.73.075003.
@article{osti_20782834,
title = {Nonuniversal Z{sup '} couplings in B decays},
author = {Chen, C.-H. and National Center for Theoretical Sciences, Taiwan and Hatanaka, Hisaki},
abstractNote = {We study the impacts of the nonuniversal Z{sup '} model, providing flavor-changing neutral current at tree level, on the branching ratios (BRs), CP asymmetries (CPAs), and polarization fractions of B decays. We find that, for satisfying the current data, the new left- and right-handed couplings have to be included at the same time. The new introduced effective interactions not only could effectively explain the puzzle of small longitudinal polarization in B{yields}K*{phi} decays, but also provide a solution to the small CPA of B{sup {+-}}{yields}{pi}{sup 0}K{sup {+-}}. We also find that the favorable CPA of B{sup {+-}}{yields}{pi}{sup 0}K{sup {+-}} is opposite in sign to the standard model; meanwhile, the CPA of B{sub d}{yields}{pi}{sup 0}K has to be smaller than -10%. In addition, by using the values of parameters which are constrained by B{yields}{pi}K, we find that the favorable ranges of BRs, CPAs, longitudinal polarizations, and perpendicular transverse polarizations for (B{sup {+-}}{yields}{rho}{sup {+-}}K*,B{sub d}{yields}{rho}{sup {+-}}K*{sup {+-}}) are (17.1{+-}3.9,10.0{+-}2.0)x10{sup -6}, (3{+-}5,21{+-}7)%, (0.66{+-}0.10,0.44{+-}0.08), and (0.14{+-}0.10,0.25{+-}0.09), respectively.},
doi = {10.1103/PHYSREVD.73.075003},
journal = {Physical Review. D, Particles Fields},
number = 7,
volume = 73,
place = {United States},
year = {Sat Apr 01 00:00:00 EST 2006},
month = {Sat Apr 01 00:00:00 EST 2006}
}
  • A nonuniversal interaction, which involves only the heavy quarks ({ital t}{sub {ital L}},{ital b}{sub {ital L}}) and {ital t}{sub {ital R}}, modifies the neutral current couplings and induces flavor-changing neutral currents (FCNC`s). The size of the FCNC effect depends crucially on the dynamics of the fermion mass generation. In this paper, we study the effect of the nonuniversal interaction on {ital Zb{bar b}}, {ital Zb{bar s}}, {ital Zd{bar s}}, and {ital Zd{bar b}}, by using an effective Lagrangian technique and assuming the quark mass matrices in the form of a generalized Fritzsch {ital Ansatz}. We point out that, if fittingmore » {ital R}{sub {ital b}}={Gamma}({ital Z}{r_arrow}{ital b{bar b}})/{Gamma}({ital Z}{r_arrow}hadrons) to the CERN LEP data within 1{sigma}, the induced FCNC couplings are very close to the allowed bounds of several rare decays.« less
  • There are theoretical and phenomenological motivations that there may exist additional heavy Z{sup '} bosons with family nonuniversal couplings. Flavor mixing in the quark and lepton sectors will then lead to flavor changing couplings of the heavy Z{sup '}, and also of the ordinary Z when Z-Z{sup '} mixing is included. The general formalism of such effects is described, and applications are made to a variety of flavor changing and CP-violating tree and loop processes. Results are described for three specific cases motivated by a specific heterotic string model and by phenomenological considerations, including cases in which all three familiesmore » have different couplings, and those in which the first two families, but not the third, have the same couplings. Even within a specific theory the results are model dependent because of unknown quark and lepton mixing matrices. However, assuming that typical mixings are comparable to the Cabibbo-Kobayashi-Maskawa matrix, processes such as coherent {mu}-e conversion in a muonic atom, K{sup 0}-K(bar sign){sup 0} and B-B(bar sign) mixing, {epsilon}, and {epsilon}{sup '}/{epsilon} lead to significant constraints on Z{sup '} bosons in the theoretically and phenomenologically motivated range M{sub Z{sup '}}{approx}1 TeV. (c) 2000 The American Physical Society.« less
  • We study the effect of a nonuniversal Z{sup '} boson in the decay modes B{yields}K{pi}. In the standard model these modes receive dominant contributions from b{yields}s QCD penguins. Therefore, in this limit one expects S{sub {pi}{sup 0}}{sub K{sup 0}}{approx_equal}sin2{beta}, A{sub {pi}{sup 0}}{sub K{sup 0}}{approx_equal}0, and A{sub {pi}{sup 0}}{sub K{sup -}}{approx_equal}A{sub {pi}{sup +}}{sub K{sup -}}. The corrections due to the presence of small nonpenguin contributions is found to yield S{sub {pi}{sup 0}}{sub K{sup 0}}>sin2{beta} and {delta}A{sub CP}(K{pi}){approx_equal}2.5%. However, the measured value of S{sub {pi}{sup 0}}{sub K{sup 0}} is less than sin2{beta} and {delta}A{sub CP}(K{pi}){approx_equal}15%. We show the model with a nonuniversalmore » Z{sup '} boson can successfully explain these anomalies.« less
  • A search for Higgs boson production in association with a W or Z boson, in the H→ W W * decay channel, is performed with a data sample collected with the ATLAS detector at the LHC in proton-proton collisions at centre-of-mass energies √s=7 TeV and 8 TeV, corresponding to integrated luminosities of 4.5 fb -1 and 20.3 fb -1, respectively. The WH production mode is studied in two-lepton and three-lepton final states, while two- lepton and four-lepton final states are used to search for the ZH production mode. The observed significance, for the combined W H and ZH production,more » is 2.5 standard deviations while a significance of 0.9 standard deviations is expected in the Standard Model Higgs boson hypothesis. The ratio of the combined W H and ZH signal yield to the Standard Model expectation, μ V H , is found to be μ V H =3.0 -1.1 + 1.3 (stat.) -0.7 +1.0 (sys.) for the Higgs boson mass of 125.36 GeV. The W H and ZH production modes are also combined with the gluon fusion and vector boson fusion production modes studied in the H → W W * → ℓνℓν decay channel, resulting in an overall observed significance of 6.5 standard deviations and μ ggF+VBF+VH=1.16 -0.15 +0.16 (stat.) -0.15 +0.18 (sys.). The results are interpreted in terms of scaling factors of the Higgs boson couplings to vector bosons (κ V ) and fermions (κ F ); the combined results are: |κ V |=1.06 -0.10 +0.10 , |κ F |=0.85 -0.20 +0.26 .« less
  • New physics associated with the heavy top quark can affect top quark production and the partial decay width of Z{r_arrow}b{bar b}. In this paper, we examine the correlated effects of possible new physics on R{sub b} measured at CERN LEP I and the single top quark production rate at the Fermilab Tevatron by using an effective Lagrangian technique. We point out that certain operators in the effective Lagrangian, constrained by the measured value of R{sub b}, can lead to significant and potentially observable effects in single top quark production. {copyright} {ital 1997} {ital The American Physical Society}