The $B_s^0\pi^\pm$ invariant mass distribution is investigated in order to search for possible exotic meson states. The analysis is based on a data sample recorded with the LHCb detector ...corresponding to $3$ fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 7$ and $8$ TeV. No significant excess is found, and upper limits are set on the production rate of the claimed $X(5568)$ state. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the $B_s^0\pi^\pm$ final state.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A study of ... meson production at LHCb is performed on proton-proton collision data, corresponding to 3.0...of integrated ...luminosity collected at centre-of-mass energies ... = 7 and 8 ... The fraction of ... mesons originating from ... decays is measured as a function of the ... transverse momentum in the rapidity range ... The radiative transition of the ... meson to ... is observed for the first time. The ... mass is determined to be ... ...where the first uncertainty is statistical and the second is systematic.
A search for $B_s^0 \to \overline{D}^{0} f_{0}(980)$ decays is performed using $3.0\, {\rm fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The $f_{0}(980)$ ...meson is reconstructed through its decay to the $\pi^{+}\pi^{-}$ final state in the mass window $900\, {\rm MeV}/c^{2} < m(\pi^{+}\pi^{-}) < 1080\, {\rm MeV}/c^{2}$. No significant signal is observed. The first upper limits on the branching fraction of $\mathcal{B}(B_s^0 \to \overline{D}^{0} f_{0}(980)) < 3.1\,(3.4) \times 10^{-6}$ are set at $90\,\%$ ($95\,\%$) confidence level.
Invariant mass distributions of B+pi- and B0pi+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb-1 of pp collision ...data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B_1(5721)^(0,+) and B_2*(5747)^(0,+) states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850--6000 MeV in both B+pi- and B0pi+ combinations. The structures are consistent with the presence of four excited B mesons, labelled B_J(5840)^(0,+) and B_J(5960)^(0,+), whose masses and widths are obtained under different hypotheses for their quantum numbers.
The Large Hadron Collider beauty experiment (LHCb) is a single-arm forward spectrometer dedicated to the study of B-meson decays in p - p collisions at the Large Hadron Collider (LHC). The LHCb ...detector has excellent tracking and particle identification capabilities. The LHCb Silicon Tracker (ST) is composed of two silicon micro-strip detectors with long readout strips. The performance of these two detectors with the first high energy p - p collisions are presented here. A detailed study of the detectors intrinsic resolution and efficiency has been performed along with precise time alignment using collision data. The latest Silicon Tracker performance results and comparison to expectations are presented.
The B 0 a B A= 0 oscillation frequency I m d is measured by the LHCb experiment using a dataset corresponding to an integrated luminosity of 1.0 fb - 1 of protonaproton collisions at s = 7 TeV , and ...is found to be I m d = 0.5156 +/- 0.0051 (stat.) +/- 0.0033 (syst.) ps - 1 . The measurement is based on results from analyses of the decays B 0 a D - pi + (D - a K + pi - pi -) and B 0 a J / I K a 0 (J / I a mu + mu - , K a 0 a K + pi -) and their charge conjugated modes.
The asymmetry in the production cross-section I of D +/- mesons, A P = I (D +) - I (D -) I (D +) + I (D -) , is measured in bins of pseudorapidity IDT and transverse momentum p T within the ...acceptance of the LHCb detector. The result is obtained with a sample of D + a K S 0 pi + decays corresponding to an integrated luminosity of 1.0 fb-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 < p T < 18.0 GeV / c and 2.20 < IDT < 4.75 , the production asymmetry is A P = (- 0.96 +/- 0.26 +/- 0.18) % . The uncertainties quoted are statistical and systematic, respectively. The result assumes that any direct CP violation in the D + a K S 0 pi + decay is negligible. No significant dependence on IDT or p T is observed.
The prompt production of charmonium I c and J / I states is studied in protonaproton collisions at a centre-of-mass energy of s = 7 TeV at the Large Hadron Collider. The I c and J / I mesons are ...identified through their decays I c a J / I gamma and J / I a mu + mu - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for I c and J / I , I (I c a J / I gamma ) / I (J / I) , is determined as a function of the J / I transverse momentum in the range 2 < p T J / I < 15 GeV / c . The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / I region.
A binned Dalitz plot analysis of B +/- a D K +/- decays, with D a K S 0 pi + pi - and D a K S 0 K + K - , is performed to measure the CP-violating observables x +/- and y +/- which are sensitive to ...the CKM angle gamma. The analysis exploits 1.0 fb - 1 of data collected by the LHCb experiment. The study makes no model-based assumption on the variation of the strong phase of the D decay amplitude over the Dalitz plot, but uses measurements of this quantity from CLEO-c as input. The values of the parameters are found to be x - = (0.0 +/- 4.3 +/- 1.5 +/- 0.6) X 10 - 2 , y - = (2.7 +/- 5.2 +/- 0.8 +/- 2.3) X 10 - 2 , x + = (- 10.3 +/- 4.5 +/- 1.8 +/- 1.4) X 10 - 2 and y + = (- 0.9 +/- 3.7 +/- 0.8 +/- 3.0) X 10 - 2 . The first, second, and third uncertainties are the statistical, the experimental systematic, and the error associated with the precision of the strong-phase parameters measured at CLEO-c, respectively. These results correspond to gamma = (44 - 38 + 43) degree , with a second solution at gamma a gamma + 180 degree , and r B = 0.07 +/- 0.04 , where r B is the ratio between the suppressed and favoured B decay amplitudes.
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