90 research outputs found
SU(3) Decomposition of Two-Body B Decay Amplitudes
We present the complete flavor SU(3) decomposition of decay amplitudes for
decays of the triplet (B^+_u, B^0_d, B^0_s) of B mesons nonleptonically into
two pseudoscalar mesons. This analysis holds for arbitrarily broken SU(3) and
can be used to generate amplitude relations when physical arguments permit one
to neglect or relate any of the reduced amplitudes.Comment: 31 pages, revtex, no figure
New Physics in Bs -> J/psi phi: a General Analysis
Recently, the CDF and D0 collaborations measured indirect CP violation in Bs
-> J/psi phi and found a hint of a signal. If taken at face value, this can be
interpreted as a nonzero phase of Bs-Bsbar mixing (beta_s), in disagreement
with the standard model, which predicts that beta_s ~= 0. In this paper, we
argue that this analysis may be incomplete. In particular, there can be new
physics (NP) in the bbar -> sbar c cbar decay. If so, the value of beta_s is
different than for the case in which NP is assumed to be present only in the
mixing. We have examined several models of NP and found that, indeed, there can
be significant contributions to the decay. These effects are consistent with
measurements in B -> J/psi K* and Bd -> J/psi Ks. Due to the NP in the decay,
polarization-dependent indirect CP asymmetries and triple-product asymmetries
are predicted in Bs -> J/psi phi.Comment: 28 pages, JHEP, no figures. Considerable changes made. Abstract and
main text of paper modified to alter presentation. Appendix added. References
added. Conclusions unchanged
New Physics in b -> s mu+ mu-: CP-Conserving Observables
We perform a comprehensive study of the impact of new-physics operators with
different Lorentz structures on decays involving the b -> s mu+ mu- transition.
We examine the effects of new vector-axial vector (VA), scalar-pseudoscalar
(SP) and tensor (T) interactions on the differential branching ratios and
forward-backward asymmetries (A_{FB}'s) of Bsbar -> mu+ mu-, Bdbar -> Xs mu+
mu-, Bsbar -> mu+ mu- gamma, Bdbar -> Kbar mu+ mu-, and Bdbar -> K* mu+ mu-,
taking the new-physics couplings to be real. In Bdbar -> K* mu+ mu-, we further
explore the polarization fraction f_L, the angular asymmetry A_T^{(2)}, and the
longitudinal-transverse asymmetry A_{LT}. We identify the Lorentz structures
that would significantly impact these observables, providing analytical
arguments in terms of the contributions from the individual operators and their
interference terms. In particular, we show that while the new VA operators can
significantly enhance most of the asymmetries beyond the Standard Model
predictions, the SP and T operators can do this only for A_{FB} in Bdbar ->
Kbar mu+ mu-.Comment: 54 pages, JHEP format, 45 figures (included). 5/6/2013: typos in K*
mu mu angular coefficients corrected, typos in Eq. (D.12) corrected, added a
missing term in I3LT in Eq. (D.16). Numerical analysis unchange
Working Group Report: Neutrino and Astroparticle Physics
This is the report of neutrino and astroparticle physics working group at
WHEPP-8. We present the discussions carried out during the workshop on selected
topics in the above fields and also indicate progress made subsequently. The
neutrino physics subgroup studied the possibilites of constraining neutrino
masses, mixing and CPT violation in lepton sector from future experiments.
Neutrino mass models in the context of abelian horizontal symmetries, warped
extra dimensions and in presence of triplet Higgs were studied. Effect of
threshold corrections on radiative magnification of mixing angles was
investigated. The astroparticle physics subgroup focused on how various
particle physics inputs affect the CMBR fluctuation spectrum, and on brane
cosmology. This report also contains an introduction on how to use the publicly
available code CMBFAST to calculate the CMBR fluctuations.Comment: Prepared for the 8th Workshop on High-Energy Physics Phenomenology
(WHEPP-8), IIT Mumbai, India, 5-16 Jan 200
New-physics contributions to the forward-backward asymmetry in B -> K* mu+ mu-
We study the forward-backward asymmetry (AFB) and the differential branching
ratio (DBR) in B -> K* mu+ mu- in the presence of new physics (NP) with
different Lorentz structures. We consider NP contributions from vector-axial
vector (VA), scalar-pseudoscalar (SP), and tensor (T) operators, as well as
their combinations. We calculate the effects of these new Lorentz structures in
the low-q^2 and high-q^2 regions, and explain their features through analytic
approximations. We find two mechanisms that can give a significant deviation
from the standard-model predictions, in the direction indicated by the recent
measurement of AFB by the Belle experiment. They involve the addition of the
following NP operators: (i) VA, or (ii) a combination of SP and T (slightly
better than T alone). These two mechanisms can be distinguished through
measurements of DBR in B -> K* mu+ mu- and AFB in B -> K mu+ mu-.Comment: 33 pages, revtex, 9 figures. Paper originally submitted with the
wrong figures. This is corrected in the replacement. An incorrect factor of 2
found in a formula. This is corrected and figures modified. Conclusions
unchanged. Typos correcte
B Physics at the Tevatron: Run II and Beyond
This report provides a comprehensive overview of the prospects for B physics
at the Tevatron. The work was carried out during a series of workshops starting
in September 1999. There were four working groups: 1) CP Violation, 2) Rare and
Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and
Spectroscopy. The report also includes introductory chapters on theoretical and
experimental tools emphasizing aspects of B physics specific to hadron
colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a
Summary.Comment: 583 pages. Further information on the workshops, including
transparencies, can be found at the workshop's homepage:
http://www-theory.lbl.gov/Brun2/. The report is also available in 2-up
http://www-theory.lbl.gov/Brun2/report/report2.ps.gz or chapter-by-chapter
http://www-theory.lbl.gov/Brun2/report
Measurement of the Decay Amplitudes of B0 --> J/psi K* and B0s --> J/psi phi Decays
A full angular analysis has been performed for the pseudo-scalar to
vector-vector decays, B0 --> J/psi K* and B_s --> J/psi phi, to determine the
amplitudes for decays with parity-even longitudinal and transverse polarization
and parity-odd transverse polarization. The measurements are based on 190 B0
candidates and 40 B_s candidates collected from a data set corresponding to 89
inverse pb of pbarp collisions at root(s) = 1.8 TeV at the Fermilab Tevatron.
In both decays the decay amplitude for longitudinal polarization dominates and
the parity-odd amplitude is found to be small.Comment: 7 pages, 3 figures, 1 tabl
Charged-Higgs phenomenology in the Aligned two-Higgs-doublet model
The alignment in flavour space of the Yukawa matrices of a general
two-Higgs-doublet model results in the absence of tree-level flavour-changing
neutral currents. In addition to the usual fermion masses and mixings, the
aligned Yukawa structure only contains three complex parameters, which are
potential new sources of CP violation. For particular values of these three
parameters all known specific implementations of the model based on discrete
Z_2 symmetries are recovered. One of the most distinctive features of the
two-Higgs-doublet model is the presence of a charged scalar. In this work, we
discuss its main phenomenological consequences in flavour-changing processes at
low energies and derive the corresponding constraints on the parameters of the
aligned two-Higgs-doublet model.Comment: 46 pages, 19 figures. Version accepted for publication in JHEP.
References added. Discussion slightly extended. Conclusions unchange
New Physics in b -> s mu+ mu-: CP-Violating Observables
We perform a comprehensive study of the impact of new-physics operators with
different Lorentz structures on CP-violating observables involving the b -> s
mu+ mu- transition. We examine the effects of new vector-axial vector (VA),
scalar-pseudoscalar (SP) and tensor (T) interactions on the CP asymmetries in
the branching ratios and forward-backward asymmetries of Bs -> mu mu, B -> Xs
mu mu, Bs -> mu mu gamma, B -> K mu mu, and B -> K* mu mu. In B -> K* mu mu, we
also explore the direct CP asymmetries in the longitudinal polarization
fraction f_L and the angular asymmetries A_T^{(2)} and A_{LT}, as well as the
triple-product CP asymmetries A_T^{(im)} and A^{(im)}_{LT}. We find that, in
almost all cases, the CP-violating observables are sensitive only to new
physics which involves VA operators. The VA new physics may therefore be
unambiguously identified by a combined analysis of future measurements of these
CP-violating observables.Comment: 26 pages, JHEP format, 21 figures. LaTeX error corrected, figures
removed and changed, a comparison with previous literature added, references
added and updated. Conclusions unchange
- …