(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A measurement of the production cross-section of Z bosons in pp collisions at ... 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 sub(T) > 20 GeV and dilepton invariant mass in the range 60 < m() < 120 GeV. The integrated cross-section from averaging the two final states is sigma sub( Z) super()=194.3 plus or minus 0.9 plus or minus 3.3 plus or minus 7.6 pb, 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 sub( eta ) super(*). Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) A study of B s 0 → η c ϕ and B s 0 → η c π + π − decays is performed using pp collision data corresponding to an ...integrated luminosity of 3.0 fb−1, collected with the LHCb detector in Run 1 of the LHC. The observation of the decay B s 0 → η c ϕ is reported, where the η c meson is reconstructed in the ..., K + K − π + π −, π + π − π + π − and K + K − K + K − decay modes and the ϕ(1020) in the K + K − decay mode. The decay B s 0 → J/ψϕ is used as a normalisation channel. Evidence is also reported for the decay B s 0 → η c π + π −, where the η c meson is reconstructed in the ... decay mode, using the decay B s 0 → J/ψπ + π − as a normalisation channel. The measured branching fractions are ... where in each case the first uncertainty is statistical, the second systematic and the third uncertainty is due to the limited knowledge of the external branching fractions. Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment ...at a centre-of-mass energy of ... TeV, corresponding to an integrated luminosity of 279 ±11 pb−1. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 ± 1.0 ± 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions. Figure not available: see fulltext.
Study of the D^sup 0^p amplitude decays Adeva, B; Ajaltouni, Z; Amhis, Y ...
The journal of high energy physics,
05/2017, Letnik:
2017, Številka:
5
Journal Article
Recenzirano
Odprti dostop
An amplitude analysis of the decay Lambda ^sub b ^ ^sup 0^ right arrowD ^sup 0^ ppi ^sup -^ is performed in the part of the phase space containing resonances in the D ^sup 0^ p channel. The study is ...based on a data sample corresponding to an integrated luminosity of 3.0 fb^sup -1^ of pp collisions recorded by the LHCb experiment. The spectrum of excited Lambda ^sub c ^ ^sup +^ states that decay into D ^sup 0^ p is studied. The masses, widths and quantum numbers of the Lambda^sub c^(2880)^sup +^ and Lambda^sub c^(2940)^sup +^ resonances are measured. The constraints on the spin and parity for the Lambda^sub c^(2940)^sup +^ state are obtained for the first time. A near-threshold enhancement in the D ^sup 0^ p amplitude is investigated and found to be consistent with a new resonance, denoted the Lambda^sub c^(2860)^sup +^, of spin 3/2 and positive parity. Figure not available: see fulltext.
Search for the charmless decay Adeva, B; Ajaltouni, Z; Amhis, Y ...
The journal of high energy physics,
05/2017, Letnik:
2017, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A search for the charmless Figure not available: see fulltext.
Using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb^{-1}, recorded by the LHCb detector at center-of-mass energies of 7 and 8 TeV, the B_{c}^{+}→D^{0}K^{+} decay ...is observed with a statistical significance of 5.1 standard deviations. By normalizing to B^{+}→Dover ¯^{0}π^{+} decays, a measurement of the branching fraction multiplied by the production rates for B_{c}^{+} relative to B^{+} mesons in the LHCb acceptance is obtained, R_{D^{0}K}=(f_{c}/f_{u})×B(B_{c}^{+}→D^{0}K^{+})=(9.3_{-2.5}^{+2.8}±0.6)×10^{-7}, where the first uncertainty is statistical and the second is systematic. This decay is expected to proceed predominantly through weak annihilation and penguin amplitudes, and is the first B_{c}^{+} decay of this nature to be observed.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract The ratio of branching fractions and the difference in CP asymmetries of the decays B + arrow right J/ + and B + ...arrow right J/psiK + are measured using a data sample of pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 3 fb-1 at centre-of-mass energies of 7 and 8 TeV. The results are ... ... where the first uncertainties are statistical and the second are systematic. Combining this result with a recent LHCb measurement of ... provides the most precise estimate to date of CP violation in the decay B + arrow right J/ψπ +, ...Figure not available: see fulltext.
Abstract Measurements of the differential branching fraction and angular moments of the decay B 0 arrow right K +pi- mu + mu - in the K +pi- invariant mass range 1330 < m(K +pi-) < 1530 MeV/c 2 are ...presented. Proton-proton collision data are used, corresponding to an integrated luminosity of 3 fb-1 collected by the LHCb experiment. Differential branching fraction measurements are reported in five bins of the invariant mass squared of the dimuon system, q 2, between 0.1 and 8.0 GeV2 /c 4. For the first time, an angular analysis sensitive to the S-, P- and D-wave contributions of this rare decay is performed. The set of 40 normalised angular moments describing the decay is presented for the q 2 range 1.1-6.0 GeV2 /c 4. Figure not available: see fulltext.
The B_{s}^{0}π^{±} 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 sqrts=7 and 8 TeV. No significant excess is found, and upper limits are set on the production rate of the claimed X(5568) state within the LHCb acceptance. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the B_{s}^{0}π^{±} final state. The same limits also apply to a possible exotic meson decaying through the chain B_{s}^{*0}π^{±}, B_{s}^{*0}→B_{s}^{0}γ where the photon is excluded from the reconstructed decays.
Phys. Lett. B 774 (2017) 139-158 The $B^0$, $B^0_s$, $B^+$ and $\Lambda^0_b$ hadron production asymmetries are
measured using a data sample corresponding to an integrated luminosity of 3.0
fb$^{-1}$, ...collected by the LHCb experiment in proton-proton collisions at
centre-of-mass energies of 7 and 8 TeV. The measurements are performed as a
function of transverse momentum and rapidity of the $b$ hadrons within the LHCb
detector acceptance. The overall production asymmetries, integrated over
transverse momentum and rapidity, are also determined.
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