595 research outputs found
Radiative corrections to hard spectator scattering in decays
We present the calculation of the next-to-leading corrections to the tree
amplitudes which appear in the description of non-leptonic B-decays in the
factorization approach. These corrections, together with radiative corrections
to the jet functions, represent the full next-to-leading contributions to the
dominant hard spectator scattering term generated by operators in the
decay amplitudes. Using obtained analytical results we estimate
branchings fractions in the physical (or BBNS) factorization scheme. We have
also found that the imaginary part generated in the hard spectator scattering
term is rather large compared to the imaginary part of the vertex contribution.Comment: text is improved and typos are corrected, accepted for publication in
JHE
Constraining the Unitarity Triangle with B -> V gamma
We discuss the exclusive radiative decays , , and in QCD factorization within the Standard
Model. The analysis is based on the heavy-quark limit of QCD. Our results for
these decays are complete to next-to-leading order in QCD and to leading order
in the heavy-quark limit. Special emphasis is placed on constraining the
CKM-unitarity triangle from these observables. We propose a theoretically clean
method to determine CKM parameters from the ratio of the decay
spectrum to the branching fraction of . The method is based on
the cancellation of soft hadronic form factors in the large energy limit, which
occurs in a suitable region of phase space. The ratio of the
and branching fractions determines the side of the
standard unitarity triangle with reduced hadronic uncertainties. The recent
Babar bound on implies , with the
limiting uncertainty coming only from the SU(3) breaking form factor ratio
. This constraint is already getting competitive with the constraint from
- mixing. Phenomenological implications from
isospin-breaking effects are briefly discussed.Comment: 23 pages, 8 figure
A mid-IR survey of the L 1641-N region with ISOCAM
We present an analysis of the L 1641 outflow region using broad-band and
narrow-band imaging data at mid-infrared wavelengths from ISOCAM. We detect a
total of 34 sources in the x region covered by
the broad-band filters. Four of these sources have no reported detection in
previous studies of the region. We find that the source previously identified
as the near-IR counter-part to the IRAS detected point-source (IRAS 05338-0624)
is not the brightest source in the wavelength region of the IRAS 12 \micron\
filter. We find instead that a nearby object (within the beam of IRAS and not
detected at near-IR wavelengths) outshines all others sources in the area by a
factor of 2. We submit that this source is likely to be the IRAS detected
point source. A comparison of the near-IR (J-H vs H-K) and mid-IR (J-K vs [6.7
um]-[14 um]) color-color plots shows only four sources with excess emission at
near-IR wavelengths, but atleast 85% of all sources show excess emission at
mid-IR wavelengths. The CVF spectra suggest a range of evolutionary status in
the program stars ranging from embedded YSOs to the young disks. When combined
with optical and near-IR age estimates, these results show active current
star-formation in the region that has been on-going for at least 2 Myr.Comment: Submitted to ApJ. Abstracted edited for arXiv submission Replaced by
version accepted by Ap
Non-factorizable Contributions to Decays
We investigate to what extent the experimental information on
branching fractions and CP asymmetries can be used to better understand the QCD
dynamics in these decays. For this purpose we decompose the independent isospin
amplitudes into factorizable and non-factorizable contributions. The former can
be estimated within the framework of QCD factorization for exclusive
decays. The latter vanish in the heavy-quark limit, , and are
treated as unknown hadronic parameters. We discuss at some length in which way
the non-factorizable contributions are treated in different theoretical and
phenomenological frameworks. We point out the potential differences between the
phenomenological treatment of power-corrections in the ``BBNS approach'', and
the appearance of power -suppressed operators in soft-collinear effective
theory (SCET). On that basis we define a handful of different (but generic)
scenarios where the non-factorizable part of isospin amplitudes is parametrized
in terms of three or four unknowns, which can be constrained by data. We also
give some short discussion on the implications of our analysis for decays. In particular, since non-factorizable QCD effects in
may be large, we cannot exclude sizeable non-factorizable effects, which
violate flavour symmetry, or even isospin symmetry (via long-distance
QED effects). This may help to explain certain puzzles in connection with
isospin-violating observables in decays.Comment: published version, minor correction
Direct CP Violation, Branching Ratios and Form Factors , in Decays
The and transitions involved in hadronic B decays are
investigated in a phenomenological way through the framework of QCD
factorization. By comparing our results with experimental branching ratios from
the BELLE, BABAR and CLEO Collaborations for all the B decays including either
a pion or a kaon, we propose boundaries for the transition form factors and depending on the CKM matrix element parameters and
. From this analysis, the form factors required to reproduce the
experimental data for branching ratios are and
. We calculate the direct CP violating asymmetry
parameter, , for and decays, in the case where mixing effects are taken into
account. Based on these results, we find that the direct CP asymmetry for
, ,
, and , reaches its maximum when the invariant mass is
in the vicinity of the meson mass. The inclusion of
mixing provides an opportunity to erase, without ambiguity, the phase
uncertainty mod in the determination of the CKM angles in case
of and in case of .Comment: 74 pages, 15 figures, 8 tables. A few misprints corrected, two
references adde
Symmetries and Asymmetries of B -> K* mu+ mu- Decays in the Standard Model and Beyond
The rare decay B -> K* (-> K pi) mu+ mu- is regarded as one of the crucial
channels for B physics as the polarization of the K* allows a precise angular
reconstruction resulting in many observables that offer new important tests of
the Standard Model and its extensions. These angular observables can be
expressed in terms of CP-conserving and CP-violating quantities which we study
in terms of the full form factors calculated from QCD sum rules on the
light-cone, including QCD factorization corrections. We investigate all
observables in the context of the Standard Model and various New Physics
models, in particular the Littlest Higgs model with T-parity and various MSSM
scenarios, identifying those observables with small to moderate dependence on
hadronic quantities and large impact of New Physics. One important result of
our studies is that new CP-violating phases will produce clean signals in
CP-violating asymmetries. We also identify a number of correlations between
various observables which will allow a clear distinction between different New
Physics scenarios.Comment: 56 pages, 18 figures, 14 tables. v5: Missing factor in eqs. (3.31-32)
and fig. 6 corrected. Minor misprints in eq. (2.10) and table A corrected.
Conclusions unchange
Heavy Quark Spectroscopy -- Theory Overview
Some recent discoveries in the spectroscopy of hadrons containing heavy
quarks, and some of their theoretical interpretations, are reviewed.Comment: 13 pages, 6 figures. Presented at Second Meeting of APS Topical Group
on Hadron Physics, Nashville, TN, 22-24. Proceedings to be published by
Journal of Physics (UK), Conference Series. Uses jpconf.cls, jpconf11.clo.
Some corrections; references update
Efficient synthesis of novel thieno[3,2-b]-, [2,3-c]- and [3,2-c]pyridones by Sonogashira coupling of bromothiophenes with terminal alkynes and subsequent intramolecular C-N bond-forming reaction
The coupling of bromothiophenes with terminal alkynes using triethylamine or diisopropyl amine under Sonogashira conditions (PdCl2(PPh 3)2, CuI) followed by subsequent addition of amines or ammonium to the intermediate thienyl acetylenes represents a novel access to a wide range of thieno[3,2-b]-, [2,3-c]-, and [3,2-c]pyridones under basic conditions and in excellent yields. © 2013 Elsevier Ltd. All rights reserved
Charged-Lepton Flavour Physics
This writeup of a talk at the 2011 Lepton-Photon symposium in Mumbai, India,
summarises recent results in the charged-lepton flavour sector. I review
searches for charged-lepton flavour violation, lepton electric dipole moments
and flavour-conserving CP violation. I also discuss recent progress in
tau-lepton physics and in the Standard Model prediction of the muon anomalous
magnetic moment.Comment: Presented at Lepton-Photon 2011, Mumbai, India; 23 pages, 14 figure
-to-Glueball form factor and Glueball production in decays
We investigate transition form factors of meson decays into a scalar
glueball in the light-cone formalism. Compared with form factors of to
ordinary scalar mesons, the -to-glueball form factors have the same power in
the expansion of . Taking into account the leading twist light-cone
distribution amplitude, we find that they are numerically smaller than those
form factors of to ordinary scalar mesons. Semileptonic ,
and decays are subsequently investigated. We
also analyze the production rates of scalar mesons in semileptonic decays
in the presence of mixing between scalar and glueball states. The
glueball production in meson decays is also investigated and the LHCb
experiment may discover this channel. The sizable branching fraction in , or could be a clear signal for a scalar glueball
state.Comment: 17 pages, 3 figure, revtex
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