897 research outputs found
Evidence for the rare decay at LHCb
A search for the rare decay is performed using
collision data recorded by the LHCb experiment at centre-of-mass energies
and TeV, corresponding to an integrated luminosity of . An excess of events is observed with respect to the background
expectations with a signal significance of 4.0 standard deviations. No
significant structure is observed in the dimuon invariant mass distribution.Comment: To appear in the Proceedings of the KAON2016 Conferenc
Production measurements at LHCb with the first data
We report on the perspective measurements of inclusive particle production in
high-energy p-p collisions with data to be collected by the LHCb experiment at
CERN's LHC. These include V0 and D meson production studies, which can be based
on a minimum bias sample, as well as charmonia production studies, which need a
muon-triggered samples. Using reconstructed decays,
both the prompt and production cross-sections will be
determined, in the forward pseudo-rapidity range of 2-5 covered by LHCb. Due to
the large production rate, such analyses will be possible with very small
integrated luminosities of the order of a few . Other
charmonia related measurements will also be discussed, such as that of the
polarization at production or of the production of some of the new X,
Y and Z states.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
Rare charm decays: an experimental review
Indirect searches, and in particular rare decays, have proven to be a
fruitful field to search for New Physics beyond the Standard Model. While the
down-quark sector (B and K) have been studied in detail, less attention was
devoted to charm decays due to the smaller expected values and higher
theoretical uncertainties of their observables. Recently a renewed interest is
growing in rare charm searches. In this article we review the current
experimental status of searches for rare decays in charmed hadrons. While the
Standard Model rates are yet to be reached, current experimental limits are
already putting constraints on New Physics models.Comment: 21 pages, 13 figures, to appear in the proceedings of The 5th
International Workshop on Charm Physics (Charm 2012
Prospects for kaon physics at LHCb
Despite not being designed for it, the LHCb experiment has given
world-leading contributions in kaon and hyperon physics. In this contribution I
review the prospects for kaon physics at LHCb exploiting the already acquired
data and the current and future Upgrade scenarios.Comment: Proceeding contribution for the International Conference on Kaon
Physics 201
LHCb commissioning
LHCb is a dedicated experiment for the study of b-hadrons, exploiting the copious production of beauty mesons and baryons in proton-proton collisions at the CERN LHC. The LHCb detector was already able to take data in September
2008 and now is being commissioned for the new LHC start-up in September 2009. Cosmic rays and single beam interactions data are in use for a study of the detectors performances and for their space and time alignment. Improvements in each
subdetector are being performed; moreover the last of the muon stations is being installed. Full experiment system tests have shown the readiness of LHCb from the data taking to their processing. Here the current status of the LHCb experiment commissioning is presented
First minimum bias physics results at LHCb
We report on the first measurements of the LHCb experiment, as obtained from
collisions at TeV and 7 TeV recorded using a minimum bias
trigger. In particular measurements of the absolute production cross
section at TeV and of the ratio both
at TeV and 7 TeV are discussed and preliminary results are
presented.Comment: To appear in the Proceedings of the 15th International QCD Conference
(QCD10) submitted to Nuc. Phys. (Proc. Suppl.
Association between attention and heart rate fluctuations in pathological worriers
Recent data suggests that several psychopathological conditions are associated with alterations in the variability of behavioral and physiological responses. Pathological worry, defined as the cognitive representation of a potential threat, has been associated with reduced variability of heart beat oscillations (i.e., decreased heart rate variability; HRV) and lapses of attention indexed by reaction times (RTs). Clinical populations with attention deficit show RTs oscillation around 0.05 and 0.01 Hz when performing a sustained attention task. We tested the hypothesis that people who are prone to worry do it in a predictable oscillating pattern revealed through recurrent lapses in attention and concomitant oscillating HRV. Sixty healthy young adults (50% women) were recruited: 30 exceeded the clinical cut-off on the Penn State Worry Questionnaire (PSWQ; High-Worry, HW); the remaining 30 constituted the Low-Worry (LW) group. After a diagnostic assessment, participants performed two 15-min sustained attention tasks, interspersed by a standardized worry-induction procedure. RTs, HRV and moods were assessed. The analyses of the frequency spectrum showed that the HW group presents a significant higher and constant peak of RTs oscillation around 0.01 Hz (period 100 s) after the induction of worry, in comparison with their baseline and with the LW group that was not responsive to the induction procedure. Physiologically, the induction significantly reduced high-frequency HRV and such reduction was associated with levels of self-reported worry. Results are coherent with the oscillatory nature of the default mode network (DMN) and further confirm an association between cognitive rigidity and autonomic nervous system inflexibility
- …