2,754 research outputs found
Searching for the B0d,s → ∅π+ π- decays
No full textUsing 3 fb-1 of pp collision data collected at √s = 7 and 8 TeV by the LHCb
experiment in the 2011 and 2012 data taking periods, the decays B⁰s → ϕπ+π-
and B⁰d → ϕπ+π- have been studied in the π+π- invariant mass range below
1600 MeV/c². The B⁰s,d → ϕπ+π- branching fractions are determined to be:
B(B⁰s → ϕπ+π-;mππ < 1600) = [3:72 ± 0:18 ± 0:38 ± 0:38] x 10-6
B(B⁰d → ϕπ+π-,mππ < 1600) = [1:75 ± 0:25 ± 0:42 ± 0:14] x 10-7
where the first uncertainty is statistical, the second is systematic, and the third
comes from the normalisation mode B⁰s → ϕϕ. From the π+π- mass distribution
and fits to angular distributions, the resonant decay mode B⁰s → ϕf₀(980) is observed and the branching fraction is measured to be:
B(B⁰s → ϕf₀(980); f₀(980) → π+π-) = [1:23 ± 0:15 ± 0:12 ± 0:12] x 10-6
The fit also requires contributions from B⁰s → ϕf2(1270). A search for a P-wave contribution from B⁰s → ϕρ⁰(770) finds evidence at ~ 4σ but confirmation will require more data. An upper limit of the B⁰s → ϕρ⁰(770) decay branching fraction
at 90% C.L. is measured to be:
B(B⁰s → ϕρ⁰(770)) < 4 x 10-
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Prompt charm production in pp collisions at √<span style="text-decoration:overline">s</span>=7 TeV
No full textCharm production at the LHC in pp collisions at s√=7 TeV is studied with the LHCb detector. The decays D0→K−π+, D+→K−π+π+, D⁎+→D0(K−π+)π+, D+s→ϕ(K−K+)π+, Λ+c→pK−π+, and their charge conjugates are analysed in a data set corresponding to an integrated luminosity of 15 nb−1. Differential cross-sections dσ/dpT are measured for prompt production of the five charmed hadron species in bins of transverse momentum and rapidity in the region 0<pT<8 GeV/c and 2.0<y<4.5. Theoretical predictions are compared to the measured differential cross-sections. The integrated cross-sections of the charm hadrons are computed in the above pT-y range, and their ratios are reported. A combination of the five integrated cross-section measurements gives
σ(cc¯)pT<8 GeV/c,2.0<y<4.5=1419±12(stat)±116(syst)±65(frag) μb,
where the uncertainties are statistical, systematic, and due to the fragmentation functions
Measurement of the inclusive φ cross-section in pp collisions at √s=7 TeV
No full textThe cross-section for inclusive φ meson production in pp collisions at a centre-of-mass energy of √s = 7 TeV has been measured with the LHCb detector at the Large Hadron Collider. The differential cross-section is measured as a function of the φ transverse momentum pT and rapidity y in the region 0.6< pT <5.0 GeV/c and 2.44< y <4.06. The cross-section for inclusive φ production in this kinematic range is σ(pp→φX)=1758±19(stat) +43−14(syst)±182(scale) μb, where the first systematic uncertainty depends on the pT and y region and the second is related to the overall scale. Predictions based on the Pythia 6.4 generator underestimate the cross-section
1ST MEASUREMENT OF GAMMA(D(S)(+)-]MU+NU)/GAMMA(D(S)(+)-]PHI-PI+)
No full textComplete Author List:
ACOSTA D, ATHANAS M, MASEK G, PAAR H, BEAN A, GRONBERG J, KUTSCHKE R, MENARY S, MORRISON RJ, NAKANISHI S, NELSON HN, NELSON TK, RICHMAN JD, RYD A, TAJIMA H, SCHMIDT D, SPERKA D, WITHERELL MS, PROCARIO M, YANG S, BALEST R, CHO K, DAOUDI M, FORD WT, JOHNSON DR, LINGEL K, LOHNER M, RANKIN P, SMITH JG, ALEXANDER JP, BEBEK C, BERKELMAN K, BESSON D, BROWDER TE, CASSEL DG, CHO HA, COFFMAN DM, DRELL PS, EHRLICH R, GALIK RS, GARCIASCIVERES M, GEISER B, GITTELMAN B, GRAY SW, HARTILL DL, HELTSLEY BK, JONES CD, JONES SL, KANDASWAMY J, KATAYAMA N, KIM PC, KREINICK DL, LUDWIG GS, MASUI J, MEVISSEN J, MISTRY NB, NG CR, NORDBERG E, OGG M, PATTERSON JR, PETERSON D, RILEY D, SALMAN S, SAPPER M, WORDEN H, WURTHWEIN F, AVERY P, FREYBERGER A, RODRIGUEZ J, STEPHENS R, YELTON J, CINABRO D, HENDERSON S, KINOSHITA K, LIU T, SAULNIER M, SHEN F, WILSON R, YAMAMOTO H, ONG B, SELEN M, SADOFF AJ, AMMAR R, BALL S, BARINGER P, COPPAGE D, COPTY N, DAVIS R, HANCOCK N, KELLY M, KWAK N, LAM H, KUBOTA Y, LATTERY M, NELSON JK, PATTON S, PERTICONE D, POLING R, SAVINOV V, SCHRENK S, WANG R, ALAM MS, KIM IJ, NEMATI B, ONEILL JJ, SEVERINI H, SUN CR, ZOELLER MM, CRAWFORD G, DAUBENMIER CM, FULTON R, FUJINO D, GAN KK, HONSCHEID K, KAGAN H, KASS R, LEE J, MALCHOW R, MORROW F, SKOVPEN Y, SUNG M, WHITE C, WHITMORE J, WILSON P, BUTLER F, FU X, KALBFLEISCH G, LAMBRECHT M, ROSS WR, SKUBIC P, SNOW J, WANG PL, WOOD M, BORTOLETTO D, BROWN DN, FAST J, MCILWAIN RL, MIAO T, MILLER DH, MODESITT M, SCHAFFNER SF, SHIBATA EI, SHIPSEY IPJ, WANG PN, BATTLE M, ERNST J, KROHA H, ROBERTS S, SPARKS K, THORNDIKE EH, WANG CH, DOMINICK J, SANGHERA S, SHELKOV V, SKWARNICKI T, STROYNOWSKI R, VOLOBOUEV I, ZADOROZHNY P, ARTUSO M, HE D, GOLDBERG M, HORWITZ N, KENNETT R, MONETI GC, MUHEIM F, MUKHIN Y, PLAYFER S, ROZEN Y, STONE S, THULASIDAS M, VASSEUR G, ZHU G, BARTELT J, CSORNA SE, EGYED Z, JAIN V, SHELDON P, AKERIB DS, BARISH B, CHADHA M, CHAN S, COWEN DF, EIGEN G, MILLER JS, OGRADY C, URHEIM J, WEINSTEIN A
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Observation of the decay ξc0 → Ω- K+
No full textcomplete author list:
Henderson S.; Kinoshita K.; Pipkin F.; Saulnier M.; Wilson R.; Wolinski J.; Xiao D.; Yamamoto H.; Sadoff A.; Ammar R.; Baringer P.; Coppage D.; Davis R.; Kelly M.; Kwak N.; Lam H.; Ro S.; Kubota Y.; Lattery M.; Nelson J.; Perticone D.; Poling R.; Schrenk S.; Wang R.; Alam M.; Kim I.; O'Neill J.; Nemati B.; Romero V.; Severini H.; Sun C.; Wang P.; Zoeller M.; Crawford G.; Fulton R.; Gan K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Morrow F.; Sung M.; Whitmore J.; Wilson P.; Butler F.; Fu X.; Kalbfleisch G.; Lambrecht M.; Skubic P.; Snow J.; Wang P.; Bortoletto D.; Brown D.; Dominick J.; McIlwain R.; Miller D.; Modesitt M.; Shibata E.; Schaffner S.; Shipsey I.; Battle M.; Ernst J.; Kroha H.; Roberts S.; Sparks K.; Thorndike E.; Wang C.; Stroynowski R.; Artuso M.; Goldberg M.; Haupt T.; Horwitz N.; Kennett R.; Moneti G.; Playfer S.; Rozen Y.; Rubin P.; Skwarnicki T.; Stone S.; Thulasidas M.; Yao W.; Zhu G.; Barnes A.; Bartelt J.; Csorna S.; Jain V.; Letson T.; Mestayer M.; Akerib D.; Barish B.; Cowen D.; Eigen G.; Stroynowski R.; Urheim J.; Weinstein A.; Morrison R.; Tajima H.; Schmidt D.; Sperka D.; Procario M.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Bebek C.; Berkelman K.; Besson D.; Browder T.; Cassel D.; Cheu E.; Coffman D.; Drell P.; Ehrlich R.; Galik R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Honscheid K.; Jones C.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Nandi S.; Ng C.; Nordberg E.; O'Grady C.; Patterson J.; Peterson D.; Riley D.; Sapper M.; Selen M.; Worden H.; Worris M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Yelton J.; Henderson S.; Yelton J.; Rodriguez J.; Freyberger A.; Avery P.; Würthwein F.; Worris M.; Worden H.; Henderson S
- …
