A search for the X(4140) state in B+ to J/psi phi K+ decays is performed with 0.37 fb-1 of pp collisions at sqrt(s)=7 TeV collected by the LHCb experiment. No evidence for this state is found, in 2.4 ...sigma disagreement with a measurement by CDF. An upper limit on its production rate is set, BR(B+ to X(4140) K+) BR(X(4140) to J/psi phi) / BR(B+ to J/psi phi K+) < 0.07 at 90% confidence level.
The asymmetry in the production cross-section σ of D± mesons,AP=σ(D+)−σ(D−)σ(D+)+σ(D−), is measured in bins of pseudorapidity η and transverse momentum pT within the acceptance of the LHCb detector. ...The result is obtained with a sample of D+→KS0π+ 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<pT<18.0 GeV/c and 2.20<η<4.75, the production asymmetry is AP=(−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+→KS0π+ decay is negligible. No significant dependence on η or pT is observed.
Searches for the lepton flavour violating decay τ−→μ−μ+μ− and the lepton flavour and baryon number violating decays τ−→p¯μ+μ− and τ−→pμ−μ− have been carried out using proton–proton collision data, ...corresponding to an integrated luminosity of 1.0 fb−1, taken by the LHCb experiment at s=7 TeV. No evidence has been found for any signal, and limits have been set at 90% confidence level on the branching fractions: B(τ−→μ−μ+μ−)<8.0×10−8, B(τ−→p¯μ+μ−)<3.3×10−7 and B(τ−→pμ−μ−)<4.4×10−7. The results for the τ−→p¯μ+μ− and τ−→pμ−μ− decay modes represent the first direct experimental limits on these channels.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Charged particle multiplicities are studied in proton-proton collisions in the forward region at a centre-of-mass energy of ......TeV with data collected by the LHCb detector. The forward spectrometer allows access to a kinematic range of ... in pseudorapidity, momenta greater than ... and transverse momenta greater than ... The measurements are performed using events with at least one charged particle in the kinematic acceptance. The results are presented as functions of pseudorapidity and transverse momentum and are compared to predictions from several Monte Carlo event generators.
A
bstract
The isospin asymmetries of
B
→
K
(∗)
μ
+
μ
−
decays and the partial branching fractions of
B
0
→
K
0
μ
+
μ
−
and
B
+
→
K
∗+
μ
+
μ
−
are measured as a function of the di-muon mass ...squared
q
2
using an integrated luminosity of 1.0 fb
−1
collected with the LHCb detector. The
B
→
Kμ
+
μ
−
isospin asymmetry integrated over
q
2
is negative, deviating from zero with over 4 σ significance. The
B
→
K
∗
μ
+
μ
−
decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay
B
0
→
K
S
μ
+
μ
−
is reported with 5.7 σ significance. Assuming that the branching fraction of
B
0
→
K
0
μ
+
μ
−
is twice that of
B
0
→
K
S
μ
+
μ
−
, the branching fractions of
B
0
→
K
0
μ
+
μ
−
and
B
→
K
∗+
μ
+
μ
−
are found to be (0
.
31
−0.06
) × 10
−6
and (1
.
16 ± 0
.
19) × 10
−6
, respectively.
First experience and results with the LHCb Silicon Tracker Fave, V.; Bay, A.; Blanc, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
The LHCb experiment is designed to perform high-precision measurements of CP violation and rare decays of b hadrons. The construction and installation of the Silicon Tracker (ST) was completed by the ...summer of 2008. Here, we report on first results obtained using the data taken during injection tests (‘TED’ run) in August and September 2008.
A search for non-resonant D(s)+→π+μ+μ− and D(s)+→π−μ+μ+ decays is performed using proton–proton collision data, corresponding to an integrated luminosity of 1.0 fb−1, at s=7TeV recorded by the LHCb ...experiment in 2011. No signals are observed and the 90% (95%) confidence level (CL) limits on the branching fractions are found to beB(D+→π+μ+μ−)<7.3(8.3)×10−8,B(Ds+→π+μ+μ−)<4.1(4.8)×10−7,B(D+→π−μ+μ+)<2.2(2.5)×10−8,B(Ds+→π−μ+μ+)<1.2(1.4)×10−7. These limits are the most stringent to date.
First observation of the decay B+ → π+μ+μ Adametz, A.; Adrover, C.; Ajaltouni, Z. ...
The journal of high energy physics,
12/2012, Letnik:
2012, Številka:
12
Journal Article
Recenzirano
Odprti dostop
A
bstract
A discovery of the rare decay
B
+
→
π
+
μ
+
μ
−
is presented. This decay is observed for the first time, with 5.2
σ
significance. The observation is made using
pp
collision data, ...corresponding to an integrated luminosity of 1.0 fb
−1
, collected with the LHCb detector. The measured branching fraction is (2.3 ± 0.6 (stat.) ± 0.1 (syst.))×10
−8
, and the ratio of the
B
+
→
π
+
μ
+
μ
−
and
B
+
→
K
+
μ
+
μ
−
branching fractions is measured to be 0.053 ± 0.014 (stat.) ± 0.001 (syst.).
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