B Physics and Charmonia Robbe, P.
Nuclear physics. Section B, Proceedings supplement,
2011, Letnik:
214, Številka:
1
Journal Article
Recent
B physics results related final states containing a charmonium are reviewed. The main progresses are related to the study of
CP violation and to the spectroscopy of exotic
X,
Y,
Z states at
B ...factories and at the Tevatron. The first signals of
B decays to charmonium have also been observed by the LHC experiments.
The first LHCb measurement of the
J
/
ψ
production cross-section is presented. The differential production cross-section is measured as a function of the
J
/
ψ
transverse momentum
p
T
in the range
p
...T
∈
0
;
10
GeV
/
c
and rapidity
y in the range
y
∈
2.5
;
4
. The analysis is based on a sample of 14.2 nb
−1 collected between April and June 2010 at the
pp Large Hadron Collider at CERN, at a center-of-mass energy
s
=
7
TeV
. The fraction of
J
/
ψ
coming from
b-hadron decays is estimated using the
J
/
ψ
pseudo-propertime.
The Belle II experiment with SuperKEKB accelerator has started beam collision in 2018. With a higher luminosity, the target of Belle II is to improve the measurement of rare B meson decays and to ...probe for new physics. The present DAQ system in Belle II is designed to operate under a maximum trigger rate of 30 kHz at expected peak luminosity, and its stability has been confirmed in the early phases of the operation so far. Considering the difficulty of maintenance and the limited performance of the current read-out system, Belle II DAQ group is preparing an upgrade by using PCI-express-based readout board (PCIe40) which is capable of a higher data throughput of 100 Gb/s. PCIe40 board is based on an Intel Arria 10 field-programmable gate array, which has 48 transceivers and PCI-express DMA architecture. The PCIe40 firmware for Belle II needs to have many functionalities, such as custom Belle2Link protocol to detector Front-End, interface to trigger and timing distribution system, data processing logic for first-level event building, and DMA implementation. This paper describes the development of each item and performance tests with various Belle II detectors' Front-End electronics (FEE), as well as the plan of integrating the new readout system in the Belle II global DAQ system.
Chronic lymphocytic leukemia patients with mutated immunoglobulin heavy-chain genes (IGHV-M), particularly those lacking poor-risk genomic lesions, often respond well to chemoimmunotherapy (CIT). DNA ...methylation profiling can subdivide early-stage patients into naive B-cell–like CLL (n-CLL), memory B-cell–like CLL (m-CLL), and intermediate CLL (i-CLL), with differing times to first treatment and overall survival. However, whether DNA methylation can identify patients destined to respond favorably to CIT has not been ascertained. We classified treatment-naive patients (n = 605) from 3 UK chemo and CIT clinical trials into the 3 epigenetic subgroups, using pyrosequencing and microarray analysis, and performed expansive survival analysis. The n-CLL, i-CLL, and m-CLL signatures were found in 80% (n = 245/305), 17% (53/305), and 2% (7/305) of IGHV-unmutated (IGHV-U) cases, respectively, and in 9%, (19/216), 50% (108/216), and 41% (89/216) of IGHV-M cases, respectively. Multivariate Cox proportional analysis identified m-CLL as an independent prognostic factor for overall survival (hazard ratio HR, 0.46; 95% confidence interval CI, 0.24-0.87; P = .018) in CLL4, and for progression-free survival (HR, 0.25; 95% CI, 0.10-0.57; P = .002) in ARCTIC and ADMIRE patients. The analysis of epigenetic subgroups in patients entered into 3 first-line UK CLL trials identifies m-CLL as an independent marker of prolonged survival and may aid in the identification of patients destined to demonstrate prolonged survival after CIT.
•DNA methylation signatures can be used to divide IGHV-mutated CLL into clinically relevant subgroups.•The memory-like DNA methylation subgroup is an independent marker of prolonged survival for patients treated with chemoimmunotherapy.
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The first observation of the decays Λb0→χc 1p K- and Λb0→χc 2p K- is reported using a data sample corresponding to an integrated luminosity of 3.0 fb-1, collected by the LHCb experiment in p p ...collisions at center-of-mass energies of 7 and 8 TeV. The following ratios of branching fractions are measured: B/(Λb0→χc 1p K-) B (Λb0→J /ψ p K-) =0.242 ±0.014 ±0.013 ±0.009 ,B/(Λb0→χc 2p K-) B (Λb0→J /ψ p K-) =0.248 ±0.020 ±0.014 ±0.009 ,B/(Λb0→χc 2p K-) B (Λb0→χc 1p K-) =1.02 ±0.10 ±0.02 ±0.05 , where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the branching fractions of the χc 1→J /ψ γ and χc 2→J /ψ γ decays. Using both decay modes, the mass of the Λb0 baryon is also measured to be mΛb0=5619.44 ±0.28 ±0.26 MeV /c2 , where the first and second uncertainties are statistical and systematic, respectively.
The CP asymmetry in the mixing of B0s and B̅0s mesons is measured in proton-proton collision data corresponding to an integrated luminosity of 3.0 fb−1, recorded by the LHCb experiment at ...centre-of-mass energies of 7 and 8 TeV. Semileptonic B0s and B̅0s decays are studied in the inclusive mode D∓sμ±νμX with the D∓s mesons reconstructed in the K+K−π∓ final state. Correcting the observed charge asymmetry for detection and background effects, the CP asymmetry is found to be assl=(0.39±0.26±0.20)%, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of assl to date, and is consistent with the prediction from the Standard Model of particle physics.
The polarization of photons produced in radiative B-s(0) decays is studied for the first time. The data are recorded by the LHCb experiment in pp collisions corresponding to an integrated luminosity ...of 3 fb(-1) at center-of-mass energies of 7 and 8 TeV. A time-dependent analysis of the B-s(0) ->phi gamma decay rate is conducted to determine the parameter A(Delta), which is related to the ratio of right-over left-handed photon polarization amplitudes in b -> s gamma transitions. A value of A(Delta) = -0.98(-0.52)(-0.20)(+0.46)(+0.23) is measured. This result is consistent with the standard model prediction within 2 standard deviations.
A time-dependent angular analysis of B0s→ψ(2S)ϕ decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0\invfb collected during Run ...1 of the LHC. The CP-violating phase and decay-width difference of the B0s system are measured to be ϕs=0.23+0.29−0.28±0.02 rad and ΔΓs=0.066+0.041−0.044±0.007 ps−1, respectively, where the first uncertainty is statistical and the second systematic. This is the first time that ϕs and ΔΓs have been measured in a decay containing the ψ(2S) resonance.
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