118998253
Search for rare $B^0_{(s)}\rightarrow \mu^+ \mu^- \mu^+ \mu^-$ decays
A search for the decays $B^0_{s}\rightarrow \mu^+ \mu^- \mu^+ \mu^-$ and $B^0 \rightarrow \mu^+ \mu^- \mu^+ \mu^-$ is performed using data, corresponding to an integrated luminosity of 1.0\ensuremath{\{\,fb}^{-1}}\xspace, collected with the LHCb detector in 2011. The number of candidates observed is consistent with the expected background and, assuming phase-space models of the decays, limits on the branching fractions are set: \{${\ensuremath{\cal B}\xspace}(B^0_{s}\rightarrow \mu^+ \mu^- \mu^+ \mu^-) < 1.6 \ (1.2) \times 10^{-8}$} and \{${\ensuremath{\cal B}\xspace}(B^0 \rightarrow \mu^+ \mu^- \mu^+ \mu^-)< 6.6 \ (5.3) \times 10^{-9}$} at 95\,% (90\,%) confidence level. In addition, limits are set in the context of a supersymmetric model which allows for the $B^0_{(s)}$ meson to decay into a scalar ($S$) and pseudoscalar particle ($P$), where $S$ and $P$ have masses of 2.5 GeV and 214.3 MeV, respectively, both resonances decay into $\mu^+\mu^-$. The branching fraction limits for these decays are \{${\ensuremath{\cal B}\xspace}(\ensuremath{B^0_{s}\rightarrow SP}\xspace) < 1.6 \ (1.2) \times 10^{-8}$} and \{${\ensuremath{\cal B}\xspace}(\ensuremath{B^0\rightarrow SP}\xspace)< 6.3 \ (5.1) \times 10^{-9}$} at 95% (90%) confidence level.
119231582
Measurement of the D ± production asymmetry in 7 TeV pp collisions
Heavy quark production in 7 TeV centre-of-mass energy pp collisions at the LHC is not necessarily flavour symmetric. The production asymmetry, A(P), between D-s(+) and D-s(-) mesons is studied using the phi pi(+/-) decay mode in a data sample of 1.0 fb(-1) collected with the LHCb detector. The difference between pi(+) and pi(-) detection efficiencies is determined using the ratios of fully reconstructed to partially reconstructed D*(+/-) decays. The overall production asymmetry in the D-s(+/-) rapidity region 2.0 to 4.5 with transverse momentum larger than 2 GeV is measured to be A(P) = (-0.33 +/- 0.22 +/- 0.10)%. This result can constrain models of heavy flavour production. (C) 2012 CERN. Published by Elsevier By. All rights reserved.
204937677
Measurement of $C\!P$ asymmetries in the decays $B^0 \rightarrow K^{*0} \mu^+ \mu^-$ and $B^+ \rightarrow K^{+} \mu^+ \mu^-$
The direct $C\!P$ asymmetries of the decays $B^0 \rightarrow K^{*0} \mu^+ \mu^-$ and $B^+ \rightarrow K^{+} \mu^+ \mu^-$ are measured using $pp$ collision data corresponding to an integrated luminosity of 3.0$\mbox{fb}^{-1}$ collected with the LHCb detector. The respective control modes $B^0 \rightarrow J/\psi K^{*0}$ and $B^+ \rightarrow J/\psi K^{+}$ are used to account for detection and production asymmetries. The measurements are made in several intervals of $\mu^+ \mu^-$ invariant mass squared, with the $\phi(1020)$ and charmonium resonance regions excluded. Under the hypothesis of zero $C\!P$ asymmetry in the control modes, the average values of the asymmetries are \begin{align} 
{\cal A}_{C\!P}(B^0 \rightarrow K^{*0} \mu^+ \mu^-) &= -0.035 \pm 0.024 \pm 0.003, \cr 
{\cal A}_{C\!P}(B^+ \rightarrow K^{+} \mu^+ \mu^-) &= \phantom{-}0.012 \pm 0.017 \pm 0.001, \end{align} where the first uncertainties are statistical and the second are due to systematic effects. Both measurements are consistent with the Standard Model prediction of small $C\!P$ asymmetry in these decays.
118506737
Measurement of CP violation in the phase space of $B^{\pm} \to K^{\pm} \pi^{+} \pi^{-}$ and $B^{\pm} \to K^{\pm} K^{+} K^{-}$ decays
The charmless decays $B^{\pm}\to K^{\pm}\pi^+\pi^-$ and $B^{\pm}\to K^{\pm}K^+K^-$ are reconstructed using data, corresponding to an integrated luminosity of 1.0 fb$^{-1}$, collected by LHCb in 2011. The inclusive charge asymmetries of these modes are measured as $A_{C\!P}(B^{\pm}\to K^{\pm}\pi^+\pi^-) = 0.032 \pm 0.008 \stat \pm 0.004 \syst \pm 0.007 (J\psi K^{\pm})$ and $A_{C\!P}(B^{\pm}\to K^{\pm}K^+K^-) = -0.043 \pm 0.009 \stat \pm 0.003 \syst \pm 0.007 (J\psi K^{\pm})$, where the third uncertainty is due to the $C\!P$ asymmetry of the $B^{\pm}\to J\psi K^{\pm}$ reference mode. The significance of $A_{C\!P}(B^{\pm}\to K^{\pm}K^+K^-)$ exceeds three standard deviations and is the first evidence of an inclusive $C\!P$ asymmetry in charmless three-body $B$ decays. In addition to the inclusive $C\!P$ asymmetries, larger asymmetries are observed in localised regions of phase space.
118038287
Measurement of the Z+b-jet cross-section in pp collisions at s$$ \sqrt{s} $$ = 7 TeV in the forward region
A bstractThe associated production of a Z boson or an off-shell photon γ* with a bottom quark in the forward region is studied using proton-proton collisions at a centre-of-mass energy of 7 TeV. The Z bosons are reconstructed in the Z/γ* → μ+μ− final state from muons with a transverse momentum larger than 20 GeV, while two transverse momentum thresholds are considered for jets (10 GeV and 20 GeV). Both muons and jets are reconstructed in the pseudorapidity range 2.0 < η < 4.5. The results are based on data corresponding to 1.0 fb−1 recorded in 2011 with the LHCb detector. The measurement of the Z+b-jet cross-section is normalized to the Z+jet cross-section. The measured cross-sections are
0.1σZ/γ*μ+μ−+b‐jet=295±60stat±51syst±10lumifb$$ \sigma \left(\ \mathrm{Z}/{\gamma}^{*}\left({\mu}^{+}{\mu}^{-}\right) + \mathrm{b}\hbox{-} \mathrm{jet}\right)=295\pm 60\ \left(\mathrm{stat}\right)\pm 51\ \left(\mathrm{syst}\right)\pm 10\ \left(\mathrm{lumi}\right)\ \mathrm{f}\mathrm{b} $$
for pT(jet) > 10 GeV, and
0.2σZ/γ*μ+μ−+b‐jet=128±36stat±22syst±5lumifb$$ \sigma \left(\mathrm{Z}/{\gamma}^{*}\left({\mu}^{+}{\mu}^{-}\right)+\mathrm{b}\hbox{-} \mathrm{jet}\right)=128\pm 36\ \left(\mathrm{stat}\right)\pm 22\ \left(\mathrm{syst}\right)\pm 5\ \left(\mathrm{lumi}\right)\ \mathrm{f}\mathrm{b} $$
for pT(jet) > 20 GeV.

122081812
Study of $\eta-\eta^{\prime}$ mixing from measurement of $B^0_{(s)} \rightarrow J/\psi \eta^{(\prime)}$ decay rates
A study of $B^0$~and $B^0_s$ meson decays into $J/\psi\eta$~and $J/\psi\eta^{\prime}$ final states is performed using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8TeV, collected by the LHCb experiment and corresponding to 3.0fb$^{-1}$ of integrated luminosity. The decay $B^0 \rightarrow J/\psi \eta^{\prime}$ is observed for thefirst time. The following ratios of branching fractions are measured: $$ \frac{\mathcal{B}(B^0 \rightarrow J/\psi \eta^{\prime})}{\mathcal{B}(B^0_s \rightarrow J/\psi \eta^{\prime})} = (2.28\pm0.65\,(stat)\,\pm0.10\,(syst)\,\pm0.13\,(f_{s}/f_{d}))\times10^{-2},$$ $$ \frac{\mathcal{B}(B^0 \rightarrow J/\psi \eta)}{\mathcal{B}(B^0_s \rightarrow J/\psi \eta)} = (1.85\pm0.61\,(stat)\,\pm0.09\,(syst)\,\pm0.11\,(f_{s}/f_{d}))\times10^{-2},$$ where the third uncertainty is related to the present knowledge of $f_{s}/f_{d}$, the ratio between the probabilities for a $b$ quark to form a $B^0_s$ or $B^0$ meson. The branching fraction ratios are used to determine the parameters of $\eta-\eta^{\prime}$ meson mixing. In addition, the first evidence for the decay $B^0_s \rightarrow \psi(2S) \eta^{\prime}$ is reported, and the relative branching fraction is measured, 
$$\frac{\mathcal{B}(B^0_s \rightarrow \psi(2S) \eta^{\prime})}{\mathcal{B}(B^0_s \rightarrow J/\psi \eta^{\prime})} = (38.7\pm9.0\,(stat)\,\pm1.3\,(syst)\,\pm0.9(\mathcal{B}))\times10^{-2},$$ 
where the third uncertainty is due to the limited knowledge of the branching fractions of $J/\psi$ and $\psi(2S)$~mesons.
122935088
Minimal models on Riemann surfaces
Abstract We extend the Coulomb gas representation of minimal model correlation functions to higher genius Riemann surfaces. Specifically, we incorporate the “BRS” structure of this representation into the operator formalism. This allows traces over the spectrum of a minimal model to be computed from traces over Fock spaces of a free scalar field. This our results are obtained by standard sewing techniques. The formulation is general, but we present here in particular the two-loop characters of the Ising model.
122010777
Spin and Statistics of Gravitational Anyons
We determine the spin and statistics of a particle in 2 + 1 dimensions coupled to linearized gravity with a Chern-Simons term. The model and the results are compared to those of the corresponding abelian vector theory. The statistics emerge from the effective particle-particle interaction, while the spin is computed using the symmetric stress tensor of the system. We find that the spin-statistics relation is satisfied. In the gravitational case we show that while stress tensors are never gauge invariant, the Poincare generators are; in particular, despite subtleties peculiar to two spatial dimensions, there are no “superpotential” ambiguities in these generators.
134540303
ELECTROEXCITATION OF DELTA IN NUCLEI
15930852
On the BRST structure of W(3) gravity coupled to c = 2 matter
We present some explicit results on the structure of singular vectors in $c=2$ Verma modules of the $\cW_3$ algebra. Using the embedding patterns of those vectors we construct resolutions for the $c=2$ irreducible modules, and thus are able to compute some of the BRST cohomology of $\cW_3$ gravity coupled to $c=2$ matter. In particular, we determine the states in the ground ring of the theory. (To appear in the proceedings of the AMS Special Session on "Geometry and Physics", USC, Los Angeles, November 5-6, 1992)
121244971
NUCLEAR HIGH MOMENTUM COMPONENTS AND Y SCALING IN ELECTRON SCATTERING