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.
Using the latest LHCb measurements of time-dependent CP violation in the decay, a U-spin relation between the decay amplitudes of and decay processes allows constraints to be placed on the angle ...gamma of the unitarity triangle and on the mixing phase . Results from an extended approach, which uses additional inputs on and decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value is determined. In an alternative analysis, the value is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.
(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.
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
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.
We have performed a search for CPT violation in neutral charm meson oscillations. While flavor mixing in the charm sector is predicted to be small by the Standard Model, it is still possible to ...investigate CPT violation through a study of the proper time dependence of a CPT asymmetry in right-sign decay rates for D0→K−π+ and D0→K+π−. This asymmetry is related to the CPT violating complex parameter ξ and the mixing parameters x and y: ACPT∝(Reξ)y−(Imξ)x. Our 95% confidence level limit is −0.0068<(Reξ)y−(Imξ)x<0.0234. Within the framework of the Standard Model Extension incorporating general CPT violation, we also find 95% confidence level limits for the expressions involving coefficients of Lorentz violation of (−2.8<N(x,y,δ)(Δa0+0.6ΔaZ)<4.8)×10−16 GeV, (−7.0<N(x,y,δ)ΔaX<3.8)×10−16 GeV, and (−7.0<N(x,y,δ)ΔaY<3.8)×10−16 GeV, where N(x,y,δ) is the factor which incorporates mixing parameters x, y and the doubly Cabibbo-suppressed to Cabibbo-favored relative strong phase δ.
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.
We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using ...data on diffractive dissociation of 500 GeV/c pi(-) into dijets from a platinum target at Fermilab experiment E791. The results show that the /q&q> light-cone asymptotic wave function describes the data well for Q2 approximately 10 (GeV/c)(2) or more. We also measured the transverse momentum distribution of the diffractive dijets.
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.
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