Search for the rare decay [Formula omitted] Aaij, R; Beteta, C. Abellán; Adeva, B ...
The European physical journal. C, Particles and fields,
08/2019, Letnik:
79, Številka:
8
Journal Article
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A search for the rare leptonic decay Formula omitted is performed using proton-proton collision data corresponding to an integrated luminosity of Formula omitted collected by the LHCb experiment. The ...search is carried out in the region where the lowest of the two Formula omitted mass combinations is below Formula omitted. The data are consistent with the background-only hypothesis and an upper limit of Formula omitted at 95% confidence level is set on the branching fraction in the stated kinematic region.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The branching fraction and direct Formula omitted asymmetry of the decay Formula omitted are measured using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of ...7 and 8 TeV, corresponding to a total integrated luminosity of 3 Formula omitted. The following results are obtained: B(B+right arrowJ/psirho+)=(3.81-0.24+0.25±0.35)x10-5,ACP(B+right arrowJ/psirho+)=-0.045-0.057+0.056±0.008,where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search for baryon-number violating Ξ_{b}^{0} oscillations is performed with a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3 fb^{-1}. ...The baryon number at the moment of production is identified by requiring that the Ξ_{b}^{0} come from the decay of a resonance Ξ_{b}^{*-}→Ξ_{b}^{0}π^{-} or Ξ_{b}^{'-}→Ξ_{b}^{0}π^{-}, and the baryon number at the moment of decay is identified from the final state using the decays Ξ_{b}^{0}→Ξ_{c}^{+}π^{-},Ξ_{c}^{+}→pK^{-}π^{+}. No evidence of baryon-number violation is found, and an upper limit at the 95% confidence level is set on the oscillation rate of ω<0.08 ps^{-1}, where ω is the associated angular frequency.
A Dalitz plot analysis of Formula omitted decays is performed using data samples of pp collisions collected with the Formula omitted detector at centre-of-mass energies of Formula omitted and Formula ...omitted, corresponding to a total integrated luminosity of Formula omitted. A satisfactory description of the data is obtained when including a contribution representing an exotic Formula omitted resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are Formula omitted and Formula omitted, respectively. The spin-parity assignments Formula omitted and Formula omitted are both consistent with the data. In addition, the first measurement of the Formula omitted branching fraction is performed and gives B(B0right arrowetac(1S)K+pi-)=(5.73±0.24±0.13±0.66)x10-4,where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A Dalitz plot analysis of
decays is performed using data samples of
collisions collected with the
detector at centre-of-mass energies of
and
, corresponding to a total integrated luminosity of
. A ...satisfactory description of the data is obtained when including a contribution representing an exotic
resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are
and
, respectively. The spin-parity assignments
and
are both consistent with the data. In addition, the first measurement of the
branching fraction is performed and gives
where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A measurement is presented of decay-time-dependent CP violation in the decays B0 → J/ψ KS0 and B0 → ψ(2S)KS0, where the J/ψ is reconstructed from two electrons and the ψ(2S) from two muons. The ...analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb−1. The CP -violation observables are measured to beCB0→J/ψKS0=0.12±0.07±0.02,SB0→J/ψKS0=0.83±0.08±0.01,CB0→ψ2SKS0=−0.05±0.10±0.01,SB0→ψ2SKS0=0.84±0.10±0.01,where C describes CP violation in the direct decay, and S describes CP violation in the interference between the amplitudes for the direct decay and for the decay after B0−B¯0 oscillation. The first uncertainties are statistical and the second are systematic. The two sets of results are compatible with the previous LHCb measurement using B0 → J/ψ KS0 decays, where the J/ψ meson was reconstructed from two muons. The averages of all three sets of LHCb results areCB0→cc¯KS0=−0.017±0.029,SB0→cc¯KS0=0.760±0.034,under the assumption that higher-order contributions to the decay amplitudes are negligible. The uncertainties include statistical and systematic contributions.
A search for the decay
is performed, based on a data sample of proton-proton collisions corresponding to an integrated luminosity of
, collected by the LHCb experiment at centre-of-mass energies of ...7 and 8
. The observed yield is consistent with the background-only hypothesis, yielding a limit on the branching fraction of
at
confidence level. This result improves the previous upper limit on the branching fraction by an order of magnitude.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Two new algorithms for use in the analysis of Formula: see text collision are developed to identify the flavour of Formula: see text mesons at production using pions and protons from the ...hadronization process. The algorithms are optimized and calibrated on data, using Formula: see text decays from Formula: see text collision data collected by LHCb at centre-of-mass energies of 7 and 8 TeV . The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a Formula: see text meson is the first of its kind.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Using decays to
-meson pairs, the inclusive production of charmonium states in
-hadron decays is studied with
collision data corresponding to an integrated luminosity of
, collected by the LHCb ...experiment at centre-of-mass energies of 7 and 8 TeV. Denoting by
the inclusive branching fraction of a
hadron to a charmonium state
that decays into a pair of
mesons, ratios
are determined as
,
,
,
,
and
. Here and below the first uncertainties are statistical and the second systematic. Upper limits at 90% confidence level for the inclusive production of
(3872),
(3915) and
states are obtained as
,
and
. Differential cross-sections as a function of transverse momentum are measured for the
and
states. The branching fraction of the decay
is measured for the first time,
. Here the third uncertainty is due to the branching fraction of the decay
, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse
polarization is observed. The measurements allow the determination of the ratio of the branching fractions for the
decays to
and
as
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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