(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The lifetime of the ... meson is measured using semileptonic decays having a ... meson and a muon in the final state. The ...data, corresponding to an integrated luminosity of ..., are collected by the LHCb detector in ... collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is ...where the first uncertainty is statistical and the second is systematic.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The polarisation of prompt ... mesons is measured by performing an angular analysis of ... decays using proton-proton ...collision data, corresponding to an integrated luminosity of 1.0..., collected by the LHCb detector at a centre-of-mass energy of 7 TeV. The polarisation is measured in bins of transverse momentum ... and rapidity ... in the kinematic region ... and ..., and is compared to theoretical models. No significant polarisation is observed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The production of ..., ... and ... mesons decaying into the dimuon final state is studied with the LHCb detector using a ...data sample corresponding to an integrated luminosity of ... collected in proton-proton collisions at a centre-of-mass energy of ... TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ... transverse momentum and rapidity, over the ranges ... GeV/... and ... The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be ...where the first uncertainty is statistical and the second systematic.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
Measurements of charm mixing parameters from the decay-time-dependent ratio of D0->K+pi- to D0->K-pi+ rates and the charge-conjugate ratio are reported. The analysis uses data, corresponding to 3 ...fb^{-1} of integrated luminosity, from proton-proton collisions at 7 and 8 TeV center-of-mass energies recorded by the LHCb experiment. In the limit of charge-parity (CP) symmetry, the mixing parameters are determined to be x'^2=(5.5 +- 4.9)x10^{-5}, y'= (4.8 +- 1.0)x10^{-3}, and R_D=(3.568 +- 0.066)x10^{-3}. Allowing for CP violation, the mixing parameters are determined separately for D0 and D0bar mesons yielding A_D = (-0.7 +- 1.9)%, for the direct CP-violating asymmetry, and 0.75 < |q/p|< 1.24 at the 68.3% confidence level, where q and p are parameters that describe the mass eigenstates of the neutral charm mesons in terms of the flavor eigenstates. This is the most precise determination of these parameters from a single experiment and shows no evidence for CP violation.
A measurement of the $C\P$ asymmetry in $B^+ \rightarrow K^+ \mu^+ \mu^-$ decays is presented using $pp$ collision data, corresponding to an integrated luminosity of 1.0${\,fb}^{-1}$, recorded by the ...LHCb experiment during 2011 at a centre-of-mass energy of 7 TeV. The measurement is performed in seven bins of $\mu^+ \mu^-$ invariant mass squared in the range ${0.05
A search for the lepton-flavour violating decays \Bsemu and \Bdemu is performed with a data sample, corresponding to an integrated luminosity of \mbox{1.0} fb$^{-1}$ of $pp$ collisions at $\sqrt{s} = ...7$\, TeV, collected by the LHCb experiment. The observed number of $B^0_s \to e^{\pm} \mu^{\mp}$ and $B^0 \to e^{\pm} \mu^{mp}$ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be $BR(B^0_s \to e^{\pm} \mu^{\mp} < 1.1 \,(1.4) \times 10^{-8}$ and $BR (B^0 \to e^{\pm} \mu^{mp} < 2.8 \,(3.7) \times 10^{-9}$ at 90% (95%) confidence level (C.L.). These limits are a factor of twenty lower than those set by previous experiments. Lower bounds on the Pati-Salam leptoquark masses are also calculated, $M_{\rm LQ} (B^0_s \to e^{\pm} \mu^{mp}) > 107$} TeV/c$^2$ and $M_{\rm LQ} (B^0 \to e^{\pm} \mu^{\mp}) > 126$ TeV/c$^2$ at 95% C.L., and are a factor of two higher than the previous bounds.
We report a measurement of the time-dependent ratio of D0->K+pi- to D0->K-pi+ decay rates in D*+-tagged events using 1.0 fb^{-1} of integrated luminosity recorded by the LHCb experiment. We measure ...the mixing parameters x'2=(-0.9+-1.3)x10^{-4}, y'=(7.2+-2.4)x10^{-3} and the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates R_D=(3.52+-0.15)x10^{-3}, where the uncertainties include statistical and systematic sources. The result excludes the no-mixing hypothesis with a probability corresponding to 9.1 standard deviations and represents the first observation of D0-D0bar oscillations from a single measurement.
Properties of the orbitally excited (L=1) $B_s$ states are studied using 1.0 fb$^{-1}$ of pp collisions at $\sqrt{s} =7$ TeV collected with the LHCb detector. The first observation of the ...$B_{s2}^*(5840)^0$ meson decaying to $B^{*+} K^- is reported, and the corresponding branching fraction measured relative to the $B^+ K^-$ decay mode. The $B_{s1}(5830)^0 \to B^{*+} K^-$ decay is observed as well. The width of the $B_{s2}^*(5840)^0$ state is measured for the first time and the masses of the two states are determined with the highest precision to date. The observation of the $B_{s2}^*(5840)^0 \to B^{*+} K^-$ decay favours the spin-parity assignment $J^P = 2^+$ for the $B_{s2}^*(5840)^0$ meson. In addition, the most precise measurement of the mass difference $m(B^{*+})-m(B^+) = 45.01 \pm 0.30 (stat) \pm 0.23 (syst)$ MeV/$c^2$ is obtained.
A search for the rare decays Bs->mu+mu- and B0->mu+mu- is performed using data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise 1.1 fb^-1 of ...proton-proton collisions at sqrt{s} = 8 TeV and 1.0 fb^-1 at sqrt{s}=7 TeV. We observe an excess of Bs -> mu+ mu- candidates with respect to the background expectation. The probability that the background could produce such an excess or larger is 5.3 x 10^-4 corresponding to a signal significance of 3.5 standard deviations. A maximum-likelihood fit gives a branching fraction of BR(Bs -> mu+ mu-) = (3.2^{+1.5}_{-1.2}) x 10^-9, where the statistical uncertainty is 95% of the total uncertainty. This result is in agreement with the Standard Model expectation. The observed number of B0 -> mu+ mu- candidates is consistent with the background expectation, giving an upper limit of BR(B0 -> mu+ mu-) < 9.4 x 10^-10 at 95% confidence level.
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