415 research outputs found
Study of the Reactions and
We evaluate the non leptonic decays and in the limit of infinitely heavy quarks, assuming the dominance of
intermediate positive parity charmed resonances. We find that the branching
ratios are of the order .Comment: 9 pages, LaTex, BARI-TH/92-13
Quantum non-demolition measurement enables macroscopic Leggett-Garg tests
We show how a test of macroscopic realism based on Leggett-Garg inequalities
(LGIs) can be performed in a macroscopic system. Using a continuous-variable
approach, we consider quantum non-demolition (QND) measurements applied to
atomic ensembles undergoing magnetically-driven coherent oscillation. We
identify measurement schemes requiring only Gaussian states as inputs and
giving a significant LGI violation with realistic experimental parameters and
imperfections. The predicted violation is shown to be due to true quantum
effects rather than to a classical invasivity of the measurement. Using QND
measurements to tighten the "clumsiness loophole" forces the stubborn
macrorealist to re-create quantum back action in his or her account of
measurement
Probing Universal Extra Dimensions through rare decays induced by transition
A few and decays induced by transition are
studied in the Standard Model and in the framework of the Appelquist, Cheng and
Dobrescu (ACD) model, which is a New Physics scenario where a single universal
extra dimension is considered. In particular, we investigate the sensitivity of
the observables to the radius of the compactified extra dimension.Comment: LaTex, 7 pages, 4 eps figures. Contribution to the International
Workshop QCD@Work 2007, June 16-20, Martina Franca - Ital
Evading 1/m_b-suppressed IR divergencies in QCDF: Bs-->KK Decays and B_{d,s} mixing
We analyze the deviations of the mixing induced CP asymmetry in B-->phi Ks
from sin(2beta), as well as the deviations of the asymmetries in Bs-->K*K*,
Bs-->phi K* and Bs-->phi phi from sin(2beta_s), that arise in SM due to penguin
pollution. We use a theoretical input which is short-distance dominated in
QCD-factorization and thus free of IR-divergencies. We also provide alternative
ways to extract angles of the unitarity triangle from penguin-mediated decays,
and give predictions for Bs-->K*K* observables.Comment: 5 pages. Talk given at the International Workshop on Quantum
Chromodynamics: QCD@Work 2007, Martina Franca, Italy, June 200
Instabilities in two flavor quark matter
I discuss briefly the instabilities of two flavor quark matter, paying
attention to the gradient instability which develops in the g2SC phase in the
Goldstone sector.Comment: 6 pages. Talk given at QCD@Work07, Martina Franca (Italy). Some typos
corrected, one reference adde
Instabilities in two flavor quark matter
I discuss briefly the instabilities of two flavor quark matter, paying
attention to the gradient instability which develops in the g2SC phase in the
Goldstone sector.Comment: 6 pages. Talk given at QCD@Work07, Martina Franca (Italy). Some typos
corrected, one reference adde
Possible crossover from BCS superconductivity to Bose-Einstein condensate in quark matter
The possibility of the crossover from the BCS pairing to the Bose-Einstein
condensate (BEC) of diquarks with going down in density is discussed in the
framework of in the Nambu Jona-Lasinio (NJL) model. We find that the quark
matter at moderate density may be close to the intermediate of the crossover,
the precursory regime to the BEC phase.Comment: 6 pages, 4 figures, Contributed to International Workshop on Quantum
Chromodynamics: QCD@Work 2007, Martina Franca, Valle d'Itria, Italy, 16-20
Jun 200
Chiral Lagrangians with tensor sources
The implementation of tensor sources in Chiral Lagrangians allows the
computation of Green functions and form factors involving tensor currents, that
is, quark bilinears of the form \bar{q}_i\sigma^{\mu\nu}q_j. Whereas only four
new terms show up at O(p^4), we find around a hundred of them at O(p^6). So it
becomes essential to ensure that this set o operators is indeed minimal and
non-redundant (i.e., it is a basis). We discuss two phenomenological
applications in the context of vector meson resonances and the radiative pion
decay.Comment: Talk given at the 4th International Worshop on Quantum
ChromoDynamics, Theory and experiment, June 16-20, 2007. Martina Franca -
Valle d'Itria - Ital
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