Summary of pre-2008 Machine Induced Background Estimates for the LHCb Experiment

This document summarizes the pre-2008 estimates of particle flux arriving at the LHCb experiment from machine (LHC) related background sources. These particles arrive in the form of showers from both beam-gas interactions in the dispersion suppression and long straight section of IR8 and from proton losses on the IR8 tertiary collimators due to betatron cleaning inefficiencies, momentum cleaning inefficiencies and elastic beam-gas interactions along the LHC beam orbit

The Beam Conditions Monitor of the LHCb Experiment

The LHCb experiment at the European Organization for Nuclear Research (CERN) is dedicated to precision measurements of CP violation and rare decays of B hadrons. Its most sensitive components are protected by means of a Beam Conditions Monitor (BCM), based on polycrystalline CVD diamond sensors. Its configuration, operation and decision logics to issue or remove the beam permit signal for the Large Hadron Collider (LHC) are described in this paper.Comment: Index Terms: Accelerator measurement systems, CVD, Diamond, Radiation detector

Opposite-side flavour tagging of B mesons at the LHCb experiment

The calibration and performance of the oppositeside flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + →J/ψK +, B0 →J/ψK ∗0 and B0 →D ∗− μ + νμ decay modes with 0.37 fb−1 of data collected in pp collisions at √ s = 7 TeV during the 2011 physics run. The oppositeside tagging power is determined in the B + → J/ψK + channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty is statistical and the second is systematic

Strong constraints on the rare decays Bs -> mu+ mu- and B0 -> mu+ mu-

A search for Bs -> mu+ mu- and B0 -> mu+ mu- decays is performed using 1.0 fb^-1 of pp collision data collected at \sqrt{s}=7 TeV with the LHCb experiment at the Large Hadron Collider. For both decays the number of observed events is consistent with expectation from background and Standard Model signal predictions. Upper limits on the branching fractions are determined to be BR(Bs -> mu+ mu-) mu+ mu-) < 1.0 (0.81) x 10^-9 at 95% (90%) confidence level.Comment: 2+6 pages; 4 figures; Accepted for publication in Physical Review Letter

Determination of the X(3872) meson quantum numbers

The quantum numbers of the X(3872) meson are determined to be JPC=1++ based on angular correlations in B+→X(3872)K+ decays, where X(3872)→π+π-J/ψ and J/ψ→μ+μ-. The data correspond to 1.0  fb-1 of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements JPC=2-+ is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) stat

Measurement of V 0 production ratios in pp collisions at s=0.9 \sqrt {s} = 0.9 and 7 TeV

The $\bar{\Lambda} / \Lambda$ and $\bar{\Lambda} / K^0_\mathrm{S}$ production ratios are measured by the LHCb detector from $0.3\,\mathrm{nb}^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$\,TeV and $1.8\,\mathrm{nb}^{-1}$ at $\sqrt{s} = 7$\,TeV. Both ratios are presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, in the ranges {$0.15 < p_\mathrm{T} < 2.50\,\mathrm{GeV}/c$} and {$2.0<y<4.5$}. Results at the two energies are in good agreement as a function of rapidity loss, $\Delta y = y_\mathrm{beam} - y$, and are consistent with previous measurements. The ratio $\bar{\Lambda} / \Lambda$, measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio $\bar{\Lambda} / K^0_\mathrm{S}$, measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected.The $\bar{\Lambda} / \Lambda$ and $\bar{\Lambda} / K^0_\mathrm{S}$ production ratios are measured by the LHCb detector from $0.3\,\mathrm{nb}^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$\,TeV and $1.8\,\mathrm{nb}^{-1}$ at $\sqrt{s} = 7$\,TeV. Both ratios are presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, in the ranges {$0.15 < p_\mathrm{T} < 2.50\,\mathrm{GeV}/c$} and {$2.0<y<4.5$}. Results at the two energies are in good agreement as a function of rapidity loss, $\Delta y = y_\mathrm{beam} - y$, and are consistent with previous measurements. The ratio $\bar{\Lambda} / \Lambda$, measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio $\bar{\Lambda} / K^0_\mathrm{S}$, measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected

First evidence of direct CP violation in charmless two-body decays of Bs0 mesons

Using a data sample corresponding to an integrated luminosity of 0.35 fb(-1) collected by LHCb in 2011, we report the first evidence of CP violation in the decays of B-s(0) mesons to K-+/-pi(-/+)pairs, A(CP)(B-s(0) -> K pi) = 0.27 +/- 0.08(stat) +/- 0.02(syst), with a significance of 3.3 sigma. Furthermore, we report the most precise measurement of CP violation in the decays of B-0 mesons to K-+/-pi(-/+) pairs, A(CP)(B-0 -> K pi) = -0.088 +/- 0.011(stat) +/- 0.008(syst), with a significance exceeding 6 sigma. RI Galli, Domenico/A-1606-2012; Coca, Cornelia/B-6015-2012; Petrolini, Alessandro/H-3782-2011; Sarti, Alessio/I-2833-2012; Carbone, Angelo/C-8289-2012; manca, giulia/I-9264-2012; de Paula, Leandro/I-9278-2012; Patrignani, Claudia/C-5223-2009; Marconi, Umberto/J-2263-2012; de Simone, Patrizia/J-3549-2012; Cardini, Alessandro/J-5736-2012; Teodorescu, Eliza/K-3044-201

Measurement of prompt hadron production ratios in pp collisions at \sqrt{s} = 0.9\mbox{ and }7~\mathrm{TeV}

The charged-particle production ratios p/p ¯ , K−/K+, π−/π+, (p+ ¯p)/(π+ +π−), (K+ +K−)/(π+ + π−) and (p + ¯p)/(K+ + K−) are measured with the LHCb detector using 0.3 nb−1 of pp collisions delivered by the LHC at √s = 0.9 TeV and 1.8 nb−1 at √s = 7 TeV. The measurements are performed as a function of transverse momentum pT and pseudorapidity η. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio p/p ¯ is also considered as a function of rapidity loss, y ≡ ybeam − y, and is used to constrain models of baryon transport

Current practice in the removal of benign endometrial polyps: a Dutch survey

The purpose of this study is to evaluate the current practice of Dutch gynecologists in the removal of benign endometrial polyps and compare these results with the results of a previous study from 2003. In 2009 Dutch gynecologists were surveyed by a mailed questionnaire about polypectomy. Gynecologists answered questions about their individual performance of polypectomy: setting, form of anesthesia, method, and instrument use. The results were compared with the results from the previous survey. The response rate was 70% (585 of 837 gynecologists). Among the respondents, 455 (78%) stated to remove endometrial polyps themselves. Polyps were mostly removed in an inpatient setting (337; 74%) under general or regional anesthesia (247; 54%) and under direct hysteroscopic vision (411; 91%). Gynecologists working in a teaching hospital removed polyps more often in an outpatient setting compared with gynecologists working in a nonteaching hospital [118 (43%) vs. 35 (19%) p < 0.001]. These results are in accordance with the results from 2003. Compared to 2003 there was an increase in the number of gynecologists performing polypectomies with local or no anesthesia [211 (46%) vs. 98 (22%), p < 0.001]. An increase was also noted in the number of gynecologists using direct hysteroscopic vision [411 (91%) vs. 290 (64%), p < 0.001] and 5 Fr electrosurgical instruments [181 (44%) vs. 56 (19%), p < 0.001]. Compared to the situation in 2003, there is an increase in removal under direct hysteroscopic vision, with 5 Fr electrosurgical instruments, using local or no anesthesia. This implies there is progress in outpatient hysteroscopic polypectomy in the Netherlands