Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userConsiderations on Xi- reconstruction in LHCb
86
0
0.0
(
0
)
Authors
F.M. Brochu
Ask ChatGPT about the research
No Arabic abstract
This paper describes an alternative method of charged hyperon reconstruction applicable to the LHCb experiment. It extends the seminal work of the FOCUS collaboration to the specific detector layout of LHCb and addresses the reconstruction ambiguities reported in their earlier work, leading to improvements in the reconstruction efficiency for the specific cases of Xi- and Omega- baryon decays to a charged meson and a Lambda baryon.
rate research
Read More
The single electron track-reconstruction efficiency is calibrated using a sample corresponding to $1.3~mathrm{fb}^{-1}$of $pp$ collision data recorded with the LHCb detector in 2017. This measurement exploits $B^+to J/psi (e^+e^-)K^+$ decays, where one of the electrons is fully reconstructed and paired with the kaon, while the other electron is reconstructed using only the information of the vertex detector. Despite this partial reconstruction, kinematic and geometric constraints allow the $B^+$-meson mass to be reconstructed and the signal to be well separated from backgrounds. This in turn allows the electron reconstruction efficiency to be measured by matching the partial track segment found in the vertex detector to tracks found by LHCbs regular reconstruction algorithms. The agreement between data and simulation is evaluated, and corrections are derived for simulated electrons in bins of kinematics. These correction factors allow LHCb to measure branching fractions involving single electrons with a systematic uncertainty below $1%$.
The determination of track reconstruction efficiencies at LHCb using $J/psirightarrowmu^{+}mu^{-}$ decays is presented. Efficiencies above $95%$ are found for the data taking periods in 2010, 2011, and 2012. The ratio of the track reconstruction efficiency of muons in data and simulation is compatible with unity and measured with an uncertainty of $0.8,%$ for data taking in 2010, and at a precision of $0.4,%$ for data taking in 2011 and 2012. For hadrons an additional $1.4,%$ uncertainty due to material interactions is assumed. This result is crucial for accurate cross section and branching fraction measurements in LHCb.
The rare B decays Bs(d)-->mumu, B-->K*mumu and Bs-->phigamma are studied using up to sim 0.41 fb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the lhcb experiment in 2010 and 2011. A search for the decays Bs(d)-->mumu, is performed with 0.41 fb^{-1} . The absence of significant signal leads to BR(Bs-->mumu<1.4 x 10^{-8} and BR(Bd-->mumu<3.2 x 10^{-9} at 95% confidence level. The forward-backward asymmetry, fraction of longitudinal polarization and differential branching fraction of B-->K*mumu, as a function of dimuon invariant mass, are measured in 0.31 fb^{-1}. The ratio of branching ratios of the radiative B decays B--> K*gamma and Bs-->phigamma h as been measured using 0.34fb^{-1}. The obtained value for the ratio is 1.52 pm 0.14 (stat) pm 0.10 (syst) pm 0.12 (f_s/f_d). Using the HFAG value for BR(Bd --> K^*gamma), BR(Bs-->phigamma) has been found to be (2.8 pm 0.5)times 10^{-5}.
We report the first observation of the doubly-strange baryon $Xi(1620)^0$ in its decay to $Xi^-pi^+$ via $Xi_c^+ rightarrow Xi^- pi^+ pi^+$ decays based on a $980,{rm fb}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The mass and width are measured to be 1610.4 $pm$ 6.0 (stat) $^{+5.9}_{-3.5}$ (syst)~MeV$/c^2$ and 59.9 $pm$ 4.8 (stat) $^{+2.8}_{-3.0}$ (syst)~MeV, respectively. We obtain 4.0$sigma$ evidence of the $Xi(1690)^0$ with the same data sample. These results shed light on the structure of hyperon resonances with strangeness $S=-2$.
The LHCb collaboration has redesigned its trigger to enable the full offline detector reconstruction to be performed in real time. Together with the real-time alignment and calibration of the detector, and a software infrastructure to make persistent the high-level physics objects produced during real-time processing, this redesign enabled the widespread deployment of real-time analysis during Run 2. We describe the design of the Run 2 trigger and real-time reconstruction, and present data-driven performance measurements for a representative sample of LHCbs physics programme.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
