Search for the decay B 0 → ϕμ + μ Aaij, R.; Eklund, Lars; Zunica, G.
The journal of high energy physics,
05/2022, Letnik:
2022, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A search for the decay B-0 -> phi mu(+) mu(-) is performed using proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV collected by the LHCb experiment and corresponding to an ...integrated luminosity of 9 fb(-1). No evidence for the B-0 -> phi mu(+) mu(-) decay is found and an upper limit on the branching fraction, excluding the 0 and charmonium regions in the dimuon spectrum, of 4.4 x 10(-3) at a 90% credibility level, relative to that of the B-s(0) -> phi mu(+) mu(-) decay, is established. Using the measured B-s(0) -> phi mu(+) mu(-) branching fraction and assuming a phase-space model, the absolute branching fraction of the decay B-0 -> phi mu(+) mu(-) in the full q(2) range is determined to be less than 3.2 x 10(-9) at a 90% credibility level.
A
bstract
The resonant structure of the doubly Cabibbo-suppressed decay
D
+
→
K
−
K
+
K
+
is studied for the first time. The measurement is based on a sample of
pp
-collision data, collected at a ...centre-of-mass energy of 8 TeV with the LHCb detector and corresponding to an integrated luminosity of 2 fb
−1
. The amplitude analysis of this decay is performed with the isobar model and a phenomenological model based on an effective chiral Lagrangian. In both models the S-wave component in the
K
−
K
+
system is dominant, with a small contribution of the
ϕ
(1020) meson and a negligible contribution from tensor resonances. The
K
+
K
−
scattering amplitudes for the considered combinations of spin (0,1) and isospin (0,1) of the two-body system are obtained from the Dalitz plot fit with the phenomenological decay amplitude.
A search is presented for a Higgs-like boson with mass in the range 45 to 195
GeV
/
c
2
decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass ...energy of 8
TeV
, collected by the LHCb experiment, corresponding to an integrated luminosity of 2
fb
-
1
. The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-section multiplied by the branching fraction at 95% confidence level is set and ranges from 22
pb
for a boson mass of 45
GeV
/
c
2
to 4
pb
for a mass of 195
GeV
/
c
2
.
A search for decays of Bc+ mesons to two charm mesons is performed for the first time using data corresponding to an integrated luminosity of 3.0fb−1, collected by the LHCb experiment in pp ...collisions at centre-of-mass energies of 7 and 8 TeV. The decays considered are Bc+→D(s)(⁎)+D‾(⁎)0 and Bc+→D(s)(⁎)+D(⁎)0, which are normalised to high-yield B+→D(s)+D‾0 decays. No evidence for a signal is found and limits are set on twelve Bc+ decay modes.
A
bstract
The differential cross-section of prompt inclusive production of long-lived charged particles in proton-proton collisions is measured using a data sample recorded by the LHCb experiment at ...a centre-of-mass energy of
$$ \sqrt{s} $$
s
= 13 TeV. The data sample, collected with an unbiased trigger, corresponds to an integrated luminosity of 5
.
4 nb
−
1
. The differential cross-section is measured as a function of transverse momentum and pseudorapidity in the ranges
p
T
∈ 80
,
10 000) MeV
/c
and
η
∈ 2
.
0
,
4
.
8) and is determined separately for positively and negatively charged particles. The results are compared with predictions from various hadronic-interaction models.
A 20-year-old patient presented to the emergency service with radial distal epiphysis after a minor trauma. The radiological examination indicated a fracture at the radial distal epiphysis on the ...background of a tumor that occupied the radial epiphysis in its entirety, with cortical burglary in some places. When consulting the oncologist, a surgical intervention for biopsy material harvesting was performed. The anatomopathological exam showed: multiple fragments microscopically representing a tumor proliferation consisting of two cell populations, mononuclear cells, densely cellular and strobe pattern; areas of infarction, haemorrhage areas, rare intratumoral osteoid formation zones; appearance of giant cell tumor. The immunohistochemical examination confirmed the anatomopathological diagnosis adding, therefore, the aggressive character and the local relapse. The oncologist decided that it did not require oncology treatment but only orthopedic treatment. Orthopedic treatment required repeated surgery at intervals of about 5 months apart, caused by tumor recurrence. The first intervention consisted of 1/ 3 distal radius resection and replacement with a graft harvested from the peroneum. Tumor recurrence after 5 months required extirpation of tumor tissue and filling of caries caused in the graft with a fluid bone substitute. Recurrence after another 5 months required removal of the graft that was invaded by the tumor and cubitusmetacarpal arthrodesis fixed with a screw plate. Currently, the patient is undergoing complementary oncology treatment finally initiated by a medical oncologist.
A
bstract
This article presents differential measurements of the asymmetry between
$$ {\varLambda}_b^0 $$
Λ
b
0
and
$$ {\overline{\varLambda}}_b^0 $$
Λ
¯
b
0
baryon production rates in proton-proton ...collisions at centre-of-mass energies of
$$ \sqrt{s} $$
s
= 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb
−
1
. The
$$ {\varLambda}_b^0 $$
Λ
b
0
baryons are reconstructed through the inclusive semileptonic decay
$$ {\varLambda}_b^0 $$
Λ
b
0
→
$$ {\varLambda}_c^{+} $$
Λ
c
+
μ
−
$$ \overline{\nu} $$
ν
¯
μ
X
. The production asymmetry is measured both in intervals of rapidity in the range 2
.
15
< y <
4
.
10 and transverse momentum in 2
< p
T
<
27 GeV/
c
. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both
$$ \sqrt{s} $$
s
= 7 and 8 TeV data, assuming no
CP
violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in P
ythia
and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in
b
-hadron production at LHC energies.
Abstract A flavour-tagged time-dependent angular analysis of $${{B} ^0_{s}} \!\rightarrow {{J /\psi }} \phi $$ B s 0 → J / ψ ϕ decays is presented where the $${J /\psi }$$ J / ψ meson is ...reconstructed through its decay to an $$e ^+e ^-$$ e + e - pair. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and $$8\text {\,Te V} $$ 8 \,Te V , corresponding to an integrated luminosity of $$3 \text {\,fb} ^{-1} $$ 3 \,fb - 1 . The $$C\!P$$ C P -violating phase and lifetime parameters of the $${B} ^0_{s} $$ B s 0 system are measured to be $${\phi _{{s}}} =0.00\pm 0.28\pm 0.07\text {\,rad}$$ ϕ s = 0.00 ± 0.28 ± 0.07 \,rad , $${\Delta \Gamma _{{s}}} =0.115\pm 0.045\pm 0.011\text {\,ps} ^{-1} $$ Δ Γ s = 0.115 ± 0.045 ± 0.011 \,ps - 1 and $${\Gamma _{{s}}} =0.608\pm 0.018\pm 0.012\text {\,ps} ^{-1} $$ Γ s = 0.608 ± 0.018 ± 0.012 \,ps - 1 where the first uncertainty is statistical and the second systematic. This is the first time that $$C\!P$$ C P -violating parameters are measured in the $${{B} ^0_{s}} \!\rightarrow {{J /\psi }} \phi $$ B s 0 → J / ψ ϕ decay with an $$e ^+e ^-$$ e + e - pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions.
The Λb0→Λc+K+K−π− decay is observed for the first time using a data sample of proton-proton collisions at centre-of-mass energies of s=7 and 8TeV collected by the LHCb detector, corresponding to an ...integrated luminosity of 3fb−1. The ratio of branching fractions between the Λb0→Λc+K+K−π− and the Λb0→Λc+Ds− decays is measured to beB(Λb0→Λc+K+K−π−)B(Λb0→Λc+Ds−)=(9.26±0.29±0.46±0.26)×10−2, where the first uncertainty is statistical, the second systematic and the third is due to the knowledge of the Ds−→K+K−π− branching fraction. No structure on the invariant mass distribution of the Λc+K+ system is found, consistent with no open-charm pentaquark signature.
A
bstract
The cross-section for inelastic proton-proton collisions at a centre-of-mass energy of 13 TeV is measured with the LHCb detector. The fiducial cross-section for inelastic interactions ...producing at least one prompt long-lived charged particle with momentum
p
> 2 GeV/
c
in the pseudorapidity range 2 <
η
< 5 is determined to be
σ
acc
= 62.2 ± 0.2 ± 2.5 mb. The first uncertainty is the intrinsic systematic uncertainty of the measurement, the second is due to the uncertainty on the integrated luminosity. The statistical uncertainty is negligible. Extrapolation to full phase space yields the total inelastic proton-proton cross-section
σ
inel
= 75.4 ± 3.0 ± 4.5 mb, where the first uncertainty is experimental and the second due to the extrapolation. An updated value of the inelastic cross-section at a centre-of-mass energy of 7 TeV is also reported.
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