Krzysztof Swientek

Dr. Krzysztof Swientek

orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 August 2023 in Physical Review D
Verified
Journal Article
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RAR. Aaij
R. Aaij
AAA. S. W. Abdelmotteleb
A. S. W. Abdelmotteleb
CBC. Abellan Beteta
C. Abellan Beteta
FAF. Abudinén
F. Abudinén
TAT. Ackernley
T. Ackernley
LCLHCb Collaboration
LHCb Collaboration
A simultaneous analysis of the B+→K+ℓ+ℓ− and B0→K*0ℓ+ℓ− decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, q2. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9  fb−1. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

27 July 2023 in Physical Review D
Verified
Journal Article
Open access
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RAR. Aaij
R. Aaij
AAA. S. W. Abdelmotteleb
A. S. W. Abdelmotteleb
CBC. Abellan Beteta
C. Abellan Beteta
FAF. Abudinén
F. Abudinén
TAT. Ackernley
T. Ackernley
LCLHCb Collaboration
LHCb Collaboration
The branching fraction B(B0→D*−τ+ντ) is measured relative to that of the normalization mode B0→D*−π+π−π+ using hadronic τ+→π+π−π+(π0)ν¯τ decays in proton-proton collision data at a center-of-mass energy of 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 2  fb−1. The measured ratio is B(B0→D*−τ+ντ)/B(B0→D*−π+π−π+)=1.70±0.10−0.10+0.11, where the first uncertainty is statistical and the second is related to systematic effects. Using established branching fractions for the B0→D*−π+π−π+ and B0→D*−μ+νμ modes, the lepton universality test R(D*−)≡B(B0→D*−τ+ντ)/B(B0→D*−μ+νμ) is calculated, R(D*−)=0.247±0.015±0.015±0.012, where the third uncertainty is due to the uncertainties on the external branching fractions. This result is consistent with the Standard Model prediction and with previous measurements.

1 May 2024 in Journal of Instrumentation
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RAR. Aaij
R. Aaij
AAA.S.W. Abdelmotteleb
A.S.W. Abdelmotteleb
CBC. Abellan Beteta
C. Abellan Beteta
FAF. Abudinén
F. Abudinén
CAC. Achard
C. Achard
SZS. Zvyagintsev
S. Zvyagintsev
The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.

27 July 2023 in Physical Review D
Verified
Journal Article
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RAR. Aaij
R. Aaij
AAA. S. W. Abdelmotteleb
A. S. W. Abdelmotteleb
CBC. Abellan Beteta
C. Abellan Beteta
FAF. Abudinén
F. Abudinén
TAT. Ackernley
T. Ackernley
LCLHCb Collaboration
LHCb Collaboration
Resonant contributions in B0→D¯D0s+π− and B+→D−Ds+π+ decays are determined with an amplitude analysis, which is performed both separately and simultaneously, where in the latter case isospin symmetry between the decays is assumed. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9  fb−1. A doubly charged spin-0 open-charm tetraquark candidate together with a neutral partner, both with masses near 2.9 GeV, are observed in the Dsπ decay channel.

1 December 2010 in Journal of Instrumentation
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HAH Abramowicz
H Abramowicz
AAA Abusleme
A Abusleme
KAK Afanaciev
K Afanaciev
JAJ Aguilar
J Aguilar
PAP Ambalathankandy
P Ambalathankandy
JZJ Zhang
J Zhang

20 February 2013 in The European Physical Journal A
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Journal Article
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WEW. Erni
W. Erni
IKI. Keshelashvili
I. Keshelashvili
BKB. Krusche
B. Krusche
MSM. Steinacher
M. Steinacher
YHY. Heng
Y. Heng
JZJ. Zmeskal
J. Zmeskal
This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the [equation]ANDA target spectrometer. The STT encloses a...