3,171 research outputs found
CP violation in charm and beauty decays at LHCb
LHCb is a dedicated heavy flavour physics precision experiment at the LHC
searching for New Physics (NP) beyond the Standard Model (SM) through the study
of very rare decays of beauty and charm-flavoured hadrons and precision
measurements of CP-violating observables. In this review I will present a
selection of recent precision measurements of CP-violating observables in the
decays of beauty and charm-flavoured hadrons. These measurements are based on
an integrated luminosity of up to collected by LHCb in 2011.Comment: Invited talk at Fourth Workshop on Theory, Phenomenology and
Experiments in Flavour Physics, 11 - 13 June 2012, Anacapri, Ital
Higgs Searches and Prospects from LEP2
The status of the search at LEP2 for the Higgs in the Standard Model (SM) and
in the minimal supersymmetric extension of the Standard Model MSSM) is
reviewed. A preliminary lower limit of 95.5/c^2 at 95% C.L. on the SM Higgs is
obtained after a preliminary analysis of the data collected at sqrt(s)= 189
GeV. For standard choices of MSSM parameter sets, the search for the neutral
Higgs bosons h and A leads to preliminary 95% C.L. exclusion lower limits of
83.5GeV/c^2 and 84.5 GeV/c^2, respectively.Comment: 6 page
Exotic charmonium-like spectroscopy at LHCb: a study of the X(3872) and of the Z(4430)^-
I will report on the recent LHCb results on the evidence for the decay
, and on the improved measurement of the
mass and width of the , the determination of its quantum numbers and
the observation of its resonant character.Comment: Presented at The Second Annual Conference on Large Hadron Collider
Physics Columbia University, New York, U.S.A June 2-7, 201
LHCb: detector performance and first physics results
LHCb is a dedicated detector for and physics at the LHC. I will
present a concise review of the detector design and performance together with a
selection of early physics results and prospects. The integrated luminosity of
collected in 2010 has already allowed LHCb to perform a
number of a very significant measurements, while the data expected for 2011
have the potential of revealing New Physics effects in the sector.Comment: Proceedings for CORFU2010-WEEK
Precision Physics at the LHC
A large number of precision measurements will be possible with the ATLAS and
CMS experiments at the CERN Large Hadron Collider (LHC). Examples from W
physics, Drell-Yan production of lepton pairs, Triple-Gauge Couplings,top
physics, Higgs and Supersymmetry are discussed.Comment: 13 pages, 9 figures, presented ate the 5th Zeuthen Workshop on
Elementary Particle Theory on "Loops and Legs in Quantum Field Theory"
Bastel/Konigstein, Germany, April 200
B Physics at LHCb
LHCb is a dedicated detector for b physics at the LHC. In this article we
present a concise review of the detector design and performance together with
the main physics goals and their relevance for a precise test of the Standard
Model and search of New Physics beyond it.Comment: 26 pages, Contribution to "Perspectives on LHC Physics", ed. G.Kane
and A.Pierc
Cosmic Flows on 100 Mpc/h Scales: Standardized Minimum Variance Bulk Flow, Shear and Octupole Moments
The low order moments, such as the bulk flow and shear, of the large scale
peculiar velocity field are sensitive probes of the matter density fluctuations
on very large scales. In practice, however, peculiar velocity surveys are
usually sparse and noisy, which can lead to the aliasing of small scale power
into what is meant to be a probe of the largest scales. Previously, we
developed an optimal ``minimum variance'' (MV) weighting scheme, designed to
overcome this problem by minimizing the difference between the measured bulk
flow (BF) and that which would be measured by an ideal survey. Here we extend
this MV analysis to include the shear and octupole moments, which are designed
to have almost no correlations between them so that they are virtually
orthogonal. We apply this MV analysis to a compilation of all major peculiar
velocity surveys, consisting of 4536 measurements. Our estimate of the BF on
scales of ~ 100 Mpc/h has a magnitude of |v|= 416 +/- 78 km/s towards Galactic
l = 282 degree +/- 11 degree and b = 6 degree +/- 6 degree. This result is in
disagreement with LCDM with WMAP5 cosmological parameters at a high confidence
level, but is in good agreement with our previous MV result without an
orthogonality constraint, showing that the shear and octupole moments did not
contaminate the previous BF measurement. The shear and octupole moments are
consistent with WMAP5 power spectrum, although the measurement noise is larger
for these moments than for the BF. The relatively low shear moments suggest
that the sources responsible for the BF are at large distances.Comment: 13 Pages, 7 figures, 4 tables. Some changes to reflect the published
versio
Supersymmetric Electroweak Renormalization of the Z-Width in the MSSM (I)
Within the framework of the MSSM, we compute the complete set of electroweak
one-loop supersymmetric quantum effects on the width of the
-boson in the on-shell renormalization scheme. Numerical analyses of the
corrections to the various partial widths into leptons and quarks are
presented. On general grounds, the average size of the electroweak SUSY
corrections to may well saturate the level of the present
theoretical uncertainties, even if considering the full supersymmetric spectrum
lying in the neighbourhood of the unaccessible LEP 200 range. Remarkably
enough, for the present values of the top quark mass, the electroweak SUSY
effects could be, globally, very close or even bigger than the electroweak SM
corrections, but opposite in sign. Therefore, in the absence of theoretical
errors, there are large regions of parameter space where one could find that,
effectively, the electroweak SM corrections are ``missing'', or even having the
``wrong'' sign. This should be helpful in discriminating between the SM and the
MSSM. However, an accurate prediction of the electroweak quantum effects on
will only be possible, if and are pinned down
in the future with enough precision.Comment: 17 p. in LaTeX. Preprint UAB-FT-343. Error in figure caption #3
corrected. Results unchange
The Values of and Derived from the Non-Observation of Electroweak Radiative Corrections at LEP: Global Fit
A set of equations representing the mass ratio and various observables
of decays in terms of , , ,
, , , and (all
other fermion masses being neglected) are compared with the latest data of the
four LEP detectors, which at the level of one standard deviation coincide with
their Born values. Our global fit gives: , where the central values
correspond to GeV, the first errors are statistical and the second
ones represent shifts of the central values corresponding to
GeV() and 60 GeV(). The predicted mass of the top is smaller than in the
recent fits by 4 GeV. The {\it predicted} values of and the LEP
observables, based on the fitted values of and , show a
weak dependence on and differ by several {\it predicted} standard
deviations from the corresponding Born values. The uncertainties of the
predicted values and their deviations from the corresponding Born values
determine the experimental accuracy required to observe electroweak radiative
corrections.Comment: LaTex, 15 pages (including 3 figures as EPS files at the end
Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions
Data taken with the ALEPH detector at LEP1 have been used to search for gamma
gamma production of the glueball candidates f0(1500) and fJ(1710) via their
decay to pi+pi-. No signal is observed and upper limits to the product of gamma
gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have
been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) <
0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV
at 95% confidence level.Comment: 10 pages, 3 figure
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