4,271 research outputs found
HFAG-charm averages
The extraction of charm mixing and CP violation parameters requires the
combination of many measurements. The latest averages are reviewed and the
contribution of individual measurements is discussed. While it is established
that the CP-even eigenstate is the shorter lived, the oscillation frequency of
charm mesons is still not known to high accuracy. All CP asymmetries are found
to be compatible with zero within less than 3 sigma.Comment: Proceedings of the 8th International Workshop on the CKM Unitarity
Triangle (CKM 2014), Vienna, Austria, September 8-12, 201
Measurement of CP asymmetries in decays
The latest measurements of the individual time-integrated CP asymmetry in the
Cabibbo-suppressed decays decays are presented. The results
are based on collision data, corresponding to an integrated luminosity of
, collected with the LHCb detector at centre-of-mass energies of 7
and 8 TeV. A combination of the asymmetries using both prompt and secondary
charm decays is presented ; .
These are the most precise measurements from a single experiment. The result
for is the most precise determination of a time-integrated CP
asymmetry in the charm sector to date, and neither measurement shows evidence
of CP asymmetry.Comment: VIII International Workshop On Charm Physics, 5-9 September, 2016,
Bologna, Ital
Direct CPV in two-body and multi-body charm decays at LHCb
The Standard Model predicts CP asymmetries in charm decays of
and the observation of significantly larger CP violation could indicate
non-Standard Model physics effects. During 2011 and 2012, the LHCb experiment
collected a sample corresponding to 3/fb yielding the world's largest sample of
decays of charmed hadrons. This allowed the CP violation in charm to be studied
with unprecedented precision in many two- body and multibody decay modes. The
most recent LHCb searches for direct CP violation are presented in these
proceedings.Comment: 6 pages, Contribution to proceedings of the 8th International
Workshop on the CKM Unitarity Triangle (CKM 2014), Vienna, Austria, September
8-12, 201
The charm physics programme at the LHCb upgrade, and Atlas and CMS upgrades
Charm physics has been established at the LHC based on several high-precision
measurements. The future of charm physics at the LHC experiments is discussed
in detail. The bulk of the charm physics programme will be performed by LHCb
and the LHCb upgrade. In particular, the impact of the LHCb upgrade on mixing
and \CP violation measurements is presented.Comment: to appear in the proceedings of The 5th International Workshop on
Charm Physics (Charm 2012
Introduction to Charm Physics
This paper gives an overview of charm physics. It is a lecture write-up aimed
at students with a minimum of prior knowledge in particle physics, but at the
same time provides a state-of-the art review of the field. The main focus is on
mixing and CP violation, which is a field with ever growing attention since
first evidence for charm mixing was observed in 2007. Other areas covered are
charm spectroscopy, production, as well as rare decays.Comment: 39 pages, 11 figures. Proceedings of the workshop "Flavorful Ways to
New Physics", October 28-31 2014, Freudenstadt, German
LHCb VELO software alignment, Part III: the alignment of the relative sensor positions
The LHCb Vertex Locator contains 42 silicon sensor modules. Each module has
two silicon sensors. A method for determining the relative alignment of the
silicon sensors within each module from data is presented. The software
implementation details are discussed. Monte-Carlo simulation studies are
described that demonstrate an alignment precision of 1.3 micron is obtained in
the sensor plane
Impact of misalignments on the analysis of B decays
This note investigates the effects of a misaligned tracking system on the
analysis of B decays. Misalignment effects of both the vertex locator and the
inner and outer T-stations have been studied. -scaling effects of the vertex
locator are also considered. It is proven that misalignments of the order of
the detector single-hit resolutions have little or negligible effects on the
quality of the reconstruction and of the analysis of B decays. The studies were
performed with a sample of decays, but the impact of
misalignments on the performance of the pattern recognition algorithms and on
the primary vertex resolutions, assessed for the first time, are rather general
and not restricted to decays
Alignment procedure of the LHCb Vertex Detector
LHCb is one of the four main experiments of the Large Hadron Collider (LHC)
project, which will start at CERN in 2008. The experiment is primarily
dedicated to B-Physics and hence requires precise vertex reconstruction. The
silicon vertex locator (VELO) has a single hit precision of better than 10
micron and is used both off-line and in the trigger. These requirements place
strict constraints on its alignment. Additional challenges for the alignment
arise from the detector being retracted between each fill of the LHC and from
its unique circular disc r/phi strip geometry. This paper describes the track
based software alignment procedure developed for the VELO. The procedure is
primarily based on a non-iterative method using a matrix inversion technique.
The procedure is demonstrated with simulated events to be fast, robust and to
achieve a suitable alignment precision.Comment: accepted for publication in NIM
ReDecay: A novel approach to speed up the simulation at LHCb
With the steady increase in the precision of flavour physics measurements
collected during LHC Run 2, the LHCb experiment requires simulated data samples
of larger and larger sizes to study the detector response in detail. The
simulation of the detector response is the main contribution to the time needed
to simulate full events. This time scales linearly with the particle
multiplicity. Of the dozens of particles present in the simulation only the few
participating in the signal decay under study are of interest, while all
remaining particles mainly affect the resolutions and efficiencies of the
detector. This paper presents a novel development for the LHCb simulation
software which re-uses the rest of the event from previously simulated events.
This approach achieves an order of magnitude increase in speed and the same
quality compared to the nominal simulation
B Physics at the LHC
The LHC is scheduled to start its first physics data taking period later in 2009. Primarily LHCb but also ATLAS and CMS will start a rich B physics programme with the potential of revealing New Physics in the heavy flavour sector. This contribution will cover the prospects for B physics at the LHC with particular emphasis to early measurements. This includes CP violation measurements in and decays, searches for rare decays such as , as well as semileptonic and radiative channels
- âŠ