Using proton-proton collision data, collected by the LHCb experiment and corresponding to the integrated luminosity of 9 fb
−1
,
the several new
decays to charmonium and three light charged hadrons ...are observed. In particular, following channels are observed
→ ψ(2S)π
+
π
−
π
+
,
→ (ψ(2S) → J/ψπ
+
π
−
)π
+
,
→ J/ψK
+
π
−
π
+
, and
→ J/ψK
+
K
−
K
+
. The first evidence of the
→ ψ(2S)K
+
K
−
π
+
decays is obtained. The branching fractions of these decays are measured with respect to the high-statistic normalization channels.
The paper presents results of the search for new
meson decays into charmonium and light hadrons in the final state. Relative branching fractions of the studied processes are measured. ...The contributions of intermediate resonant structures in light hadron systems are considered. Experimental data and theoretical predictions are compared for various mass combinations. The analysis is based on the data collected by the LHCb experiment in proton—proton collisions at the center-of-mass energies of 7, 8, and 13 TeV in the period from 2011 to 2018.
The first observation of the
→ χ
c
1
(3872)pK
–
decay and the results of precision measurements of χ
c
1
(3872) state parameters in the B
+
→ χ
c
1
(3872)K
+
decays are presented. Relative branching ...fractions of
→ χ
c
1
(3872)pK
–
and
→ ψ(2S)pK
–
decays, as well as B
+
→ χ
c
1
(3872)K
+
and B
+
→ ψ(2S)K
+
are measured. The χ
c
1
(3872) state mass is determined with high accuracy, and the natural particle width is measured for first time. The study is performed using the data collected by the LHCb detector in proton–proton collisions at center-of-mass energies of 7, 8, and 13 TeV.
The Hadron Calorimeter of LHCb (HCAL) is one of the four sub-detectors of the experiment calorimetric system, which also includes: Scintillator Pad Detector (SPD), Pre-Shower Detector (PS), and ...electromagnetic (ECAL) calorimeter. The main purpose of HCAL is to provide data for Level-0 trigger for selection events with high transverse energy hadrons. It is important to have a precise and reliable calibration system which produces result immediately after the calibration run. LHCb HCAL is equipped with a calibration system based on 137Cs radioactive source embedded into the calorimeter structure. It allows to obtain absolute calibration with good precision and monitor technical condition of the detector.
The intrinsic background of a LaBr
3
(Ce) scintillator with a diameter of 5 mm and a height of 10 mm has been studied in comparison with LYSO and CeBr
3
scintillators. It is shown that due to its ...high energy resolution the detector based on a LaBr
3
(Ce) crystal exhibits the lowest background count rate in a specified amplitude range. The measured energy resolution of the detector based on a LaBr
3
(Ce) crystal with dimensions of Ø5 mm × 10 mm in combination with a silicon photomultiplier with an active area of 3 × 3 mm
2
are presented. It is demonstrated that a detector array with the proposed configuration (a scintillator + a silicon photomultiplier enclosed in a common container) exhibits an energy resolution of 4% for 661.7-keV γ rays and a background count rate of ~0.39 cps in the energy range of (140 ± 3σ) keV.
The results of measurements of nonuniformities of the response of heterogeneous cellular electromagnetic calorimeter prototypes are presented. The features of technology solutions used in developing ...calorimetric modules under study are presented.
The calibration and performance of the LHCb Calorimeter system in Run 1 and 2 at the LHC are described. After a brief description of the sub-detectors and of their role in the trigger, the ...calibration methods used for each part of the system are reviewed. The changes which occurred with the increase of beam energy in Run 2 are explained. The performances of the calorimetry for \(\gamma\) and \(\pi^0\) are detailed. A few results from collisions recorded at \(\sqrt {s}\) = 7, 8 and 13 TeV are shown.
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