Open Charm Spectroscopy and Mass Measurements in LHCb

A study of $D^+\pi^-$, $D^0 \pi^+$ and $D^{*+}\pi^-$ final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 $fb^{-1}$, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The $D_1(2420)^0$ resonance is observed in the $D^{*+}\pi^-$ final state and the $D^*_2(2460)$ resonance is observed in the $D^+\pi^-$, $D^0 \pi^+$ and $D^{*+}\pi^-$ final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the $D^{*+}\pi^-$, $D^+\pi^-$ and $D^0 \pi^+$ final states. Using three- and four-body decays of $D$ mesons produced in semileptonic $b$-hadron decays, precision measurements of $D$ meson mass differences are made together with a measurement of the $D^{0}$ mass.Comment: 11 pages, 6 figures, 2 tables, to appear in the proceedings of The 6th International Workshop on Charm Physics (CHARM 2013

Open charm Spectroscopy and exotic states at LHCb

We present a summary of new experimental results on the status of the charm spectroscopy using inclusive approaches and Dalitz plot analyses of $B$ and $B_s$ decays. We also report on a new determination of the $X(3872)$ quantum numbers.Comment: To be published in the proceedings of CHARM-2015, Detroit, MI, 18-22 May 201

Three body decays of D0 and DS mesons

Results are presented on the study of three body decays of D0 -> K0s h+ h-, where h=pi/K and DS+ -> K0S K0S pi+. The data have been collected by the BaBar experiment at SLAC and are extracted from continuum e+ e- annihilations at the Upsilon(4S) energy.Comment: 11 pages, 13 postscript figues, contributed to the Proceedings of Hadron 2001, IX International Conference on Hadron Spectroscopy, Protvino, Russi

Study of ϒ(1S) radiative decays to γπ+π- and γK+K-

We study the ϒ(1S) radiative decays to γπ+π- and γK+K- using data recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e- collider at center-of-mass energies at the ϒ(2S) and ϒ(3S) resonances. The ϒ(1S) resonance is reconstructed from the decay ϒ(nS) → π+π-ϒ(1S), n = 2, 3

Search for the rare decays B0→J/ψγB^{0}\to J/\psi \gamma and Bs0→J/ψγB^{0}_{s} \to J/\psi \gamma

A search for the rare decay of a $B^{0}$ or $B^{0}_{s}$ meson into the final state $J/\psi\gamma$ is performed, using data collected by the LHCb experiment in $pp$ collisions at $\sqrt{s}=7$ and $8$ TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$. The observed number of signal candidates is consistent with a background-only hypothesis. Branching fraction values larger than $1.7\times 10^{-6}$ for the $B^{0}\to J/\psi\gamma$ decay mode are excluded at 90% confidence level. For the $B^{0}_{s}\to J/\psi\gamma$ decay mode, branching fraction values larger than $7.4\times 10^{-6}$ are excluded at 90% confidence level, this is the first branching fraction limit for this decay.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-044.htm

Measurement of the forward Z boson production cross-section in pp collisions at s=13\sqrt{s} = 13 TeV

A measurement of the production cross-section of Z bosons in pp collisions at $\sqrt{s} = 13$ TeV is presented using dimuon and dielectron final states in LHCb data. The cross-section is measured for leptons with pseudorapidities in the range $2.0 \eta 4.5$, transverse momenta $p_\text{T} 20$ GeV and dilepton invariant mass in the range $60 m(\ell\ell) 120$ GeV. The integrated cross-section from averaging the two final states is \begin{equation*}\sigma_{\text{Z}}^{\ell\ell} = 194.3 \pm 0.9 \pm 3.3 \pm 7.6\text{ pb,}\end{equation*} where the first uncertainty is statistical, the second is due to systematic effects, and the third is due to the luminosity determination. In addition, differential cross-sections are measured as functions of the Z boson rapidity, transverse momentum and the angular variable $\phi^*_\eta$

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

Measurement of Semileptonic B Decays Into Orbitally-Excited Charm Mesons

The authors present a study of B decays into semileptonic final states containing charged and neutral D{sub 1}(2420) and D*{sub 2}(2460). The analysis is based on a data sample of 208 fb{sup -1} collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. With a simultaneous fit to four different decay chains, the semileptonic branching fractions are extracted from measurements of the mass difference {Delta}m = m(D**)-m(D) distributions. Product branching fractions are determined to be {Beta}(B{sup +} {yields} D{sub 1}{sup 0}{ell}{sup +}{nu}{sub {ell}}) x {Beta}(D{sub 1}{sup 0} {yields} D*{sup +}{pi}{sup -}) = (2.97 {+-} 0.17 {+-} 0.17) x 10{sup -3}, {Beta}(B{sup +} {yields} D*{sub 2}{sup 0}{ell}{sup +}{nu}{sub {ell}}) x {Beta}(D*{sub 2}{sup 0} {yields} D{sup (*)+} {pi}{sup -}) = (2.29 {+-} 0.23 {+-} 0.21) x 10{sup -3}, {Beta}(B{sup 0} {yields} D{sub 1}{sup -}{ell}{sup +}{nu}{sub {ell}}) x {Beta}(D{sub 1}{sup -} {yields} D*{sup 0}{pi}{sup -}) = (2.78 {+-} 0.24 {+-} 0.25) x 10{sup -3} and {Beta}(B{sup 0} {yields} D*{sub 2}{sup -}{ell}{sup +}{nu}{sub {ell}}) x {Beta}(D*{sub 2}{sup -} {yields} D{sup (*)0} {pi}{sup -}) = (1.77 {+-} 0.26 {+-} 0.11) x 10{sup -3}. In addition they measure the branching ratio {Lambda}(D*{sub 2} {yields} D{pi}{sup 0})/{Lambda}(D*{sub 2} {yields} D{sup (*)}{pi}{sup -}) = 0.62 {+-} 0.03 {+-} 0.02

Improved Measurement of CP Observables in B- to D0_CP K- Decays

We present a study of the decay B{sup -} {yields} D{sub (CP)}{sup 0}K{sup -} and its charge conjugate, where D{sub (CP)}{sup 0} is reconstructed in both a non-CP flavor eigenstate and in CP (CP-even and CP-odd) eigenstates, based on a sample of 382 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. We measure the direct CP asymmetries A{sub CP{+-}} and the ratios of the branching fractions R{sub CP{+-}}: A{sub CP+} = 0.27 {+-} 0.09(stat) {+-} 0.04(syst), A{sub CP-} = -0.09 {+-} 0.09(stat) {+-} 0.02(syst), R{sub CP+} = 1.06 {+-} 0.10(stat) {+-} 0.05(syst), R{sub CP-} = 1.03 {+-} 0.10(stat) {+-} 0.05(syst). These results will help to better constrain the gamma phase parameter of the Cabibbo-Kobayashi-Maskawa quark mixing matrix