5,831 research outputs found

### Factorization in B -> K pi e+e- decays

We derive factorization relations for the transverse helicity amplitudes in
the rare decays B-> K\pi l+l- at leading order in Lambda/m_b, in the
kinematical region with an energetic kaon and a soft pion. We identify and
compute a new contribution of leading order in Lambda/m_b to the B->K\pi l+l-
amplitude, which is not present in the one-body decay B-> K*l+l-. As an
application we study the forward-backward asymmetry (FBA) of the lepton
momentum angular distribution in B-> K\pi l+l- decays away from the K*
resonance. The FBA in these decays has a zero at q0^2 = q0^2(M_{Kpi}), which
can be used, in principle, for determining the Wilson coefficients C_{7,9} and
testing the Standard Model. We point out that the slope of the q0^2(M_{Kpi}^2)
curve contains the same information about the Wilson coefficients as the
location of the zero, but is less sensitive to unknown nonperturbative
dynamics. We estimate the location of the zero at leading order in
factorization, and using a resonant model for the B -> K\pi l+l-
nonfactorizable amplitude.Comment: 16 pages, 5 figures. Version to appear in Physical Review D. One new
observable introduced and considered - the slope of the zero of the
forward-backward asymmetry as function of the K\pi invariant mas

### Heavy Meson Physics: What have we learned in Twenty Years?

I give a personal account of the development of the field of heavy quarks.
After reviewing the experimental discovery of charm and bottom quarks, I
describe how the field's focus shifted towards determination of CKM elements
and how this has matured into a precision science.Comment: This talk was presented during the ceremony awarding the Medalla 2003
of the Division of Particles and Fields of The Mexican Phsyical Society, at
the IX Mexican Workshop on Particles and Fields; submitted for proceedings; 9
pages, 9 figures; replacement: fix multiple typo

### Lepton non-universality in $B$ decays and fermion mass structure

We consider the possibility that the neutral-current $B$ anomalies are due to
radiative corrections generated by Yukawa interactions of quarks and leptons
with new vector-like quark and lepton electroweak doublets and new Standard
Model singlet scalars. We show that the restricted interactions needed can
result from an underlying Abelian family symmetry and that the same symmetry
can give rise to an acceptable pattern of quark and charged lepton masses and
mixings, providing a bridge between the non-universality observed in the
B-sector and that of the fermion mass matrices. We construct two simple models,
one with a single singlet scalar in which the flavour changing comes from quark
and lepton mixing and one with an additional scalar in which the flavour
changing can come from both fermion and scalar mixing. We show that for the
case the new quarks are much heavier than the new leptons and scalars the $B$
anomalies can be due to box diagrams with couplings in the perturbative regime
consistent with the bounds coming from $B_s- \bar B_s$, $K- \bar K$ and $D-
\bar D$ mixing as well as other lepton family number violating processes. The
new states can be dark matter candidates and, in the two scalar model with a
light scalar of O(60) GeV and vector-like lepton of O(100) GeV, there can be a
simultaneous explanation of the B-anomalies, the muon anomalous magnetic moment
and the dark matter abundance.Comment: Replacement contains few additional reference

### The Lee-Wick Standard Model

We construct a modification of the standard model which stabilizes the Higgs
mass against quadratically divergent radiative corrections, using ideas
originally discussed by Lee and Wick in the context of a finite theory of
quantum electrodynamics. The Lagrangian includes new higher derivative
operators. We show that the higher derivative terms can be eliminated by
introducing a set of auxiliary fields; this allows for convenient computation
and makes the physical interpretation more transparent. Although the theory is
unitary, it does not satisfy the usual analyticity conditions.Comment: 20 pages, 4 figures. Improved discussion and reference added. Contour
prescription clarifie

Recommended from our members

### An introduction to the theory of heavy mesons and baryons

Introductory lectures (delivered at TASI, June 1994) on heavy quarks and heavy quark effective field theory. Applications to inclusive semileptonic decays and to interactions with light mesons are covered in detail

### Massive Vector Scattering in Lee-Wick Gauge Theory

We demonstrate that amplitudes describing scattering of longitudinally
polarized massive vector bosons present in non-Abelian Lee-Wick gauge theory do
not grow with energy and, hence, satisfy the constraints imposed by
perturbative unitarity. This result contrasts with the widely-known violation
of perturbative unitarity in the standard model with a very heavy Higgs. Our
conclusions are valid to all orders of perturbation theory and depend on the
existence of a formulation of the theory in which all operators are of
dimension four or less. This can be thought of as a restriction on the kinds of
higher dimension operator which can be included in the higher derivative
formulation of the theory.Comment: 11 pages, no figure

### Magnetic Wormholes and Vertex Operators

We consider wormhole solutions in $2+1$ Euclidean dimensions. A duality
transformation is introduced to derive a new action from magnetic wormhole
action of Gupta, Hughes, Preskill and Wise. The classical solution is
presented. The vertex operators corresponding to the wormhole are derived.
Conformally coupled scalars and spinors are considered in the wormhole
background and the vertex operators are computed. ( To be published in Phys.
Rev. D15)Comment: 18 pages of RevTex, preprint IP/BBSR/94-2

### Operator Product Expansion for Exclusive Decays: B^+ ->Ds^+ e+e- and B^+ -> Ds^{*+} e+e-

The decays $B^+\to D_{s,d}^+e^+e^-$ and $B^+\to D_{s,d}^{*+}e^+e^-$ proceed
through a weak and an electromagnetic interaction. This is a typical ``long
distance'' process, usually difficult to compute systematically. We propose
that over a large fraction of phase space a combination of an operator product
and heavy quark expansions effectively turns this process into one in which the
weak and electromagnetic interactions occur through a local operator. Moreover,
we use heavy quark spin symmetry to relate all the local operators that appear
in leading order of the operator expansion to two basic ones. We use this
operator expansion to estimate the decay rates for $B^+\to
D_{s,d}^{(*)+}e^+e^-$.Comment: 4 pages, 1 figure, Latex, published version in PR

- â€¦