scholarly journals Luminosity Measurements at the LHC at CERN Using Medipix, Timepix and Timepix3 Devices

Physics ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 579-654
Author(s):  
André Sopczak
Keyword(s):  
Hadron Collider ◽  
Precise Determination ◽  
Particle Accelerator ◽  
Proton Proton ◽  
Performance Improvements ◽  
Long Term Stability ◽  
Pixel Detectors ◽  
Relative Luminosity ◽  
Radiation Induced

The precise determination of the luminosity is essential for many analyses in physics based on the data from the particle accelerator Large Hadron Collider (LHC) at CERN. There are different types of detectors used for the luminosity measurements. The focus of this review is on luminosity measurements with hybrid-pixel detectors and the progress made over the past decade. The first generations of detectors of the Medipix and Timepix families had frame-based readout, while Timepix3 has a quasi-continuous readout. The applications of the detectors are manifold, and in particular, the detectors have been operated in the harsh environment of the LHC. The excellent performance in detecting high fluxes of elementary particles made these detectors ideal tools to measure the delivered luminosity resulting from proton–proton collisions. Important aspects of this review are the performance improvements in relative luminosity measurements from one detector generation to another, the long-term stability of the measurements, absolute luminosity measurements, material activation (radiation-induced) corrections, and the measurement of luminosity from neutron counting. Rather than bunch-average luminosity provided by previous detector generations, owing to the excellent time-resolution, Timepix3 measured the luminosity of individual proton bunches that are 25 ns apart. This review demonstrates the large progress in the precision of luminosity measurements during LHC Run-1 and Run-2 operations using hybrid-pixel detectors, and thus their importance for luminosity measurements in the future of LHC operations.

scholarly journals Precise determination of the $$B_{\mathrm{s}}^0$$–$$\overline B_{\mathrm{s}}^0$$ oscillation frequency

2022 ◽  
Author(s):  
◽  
R. Aaij ◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Oscillation Frequency ◽  
Strange Quark ◽  
Mass Difference ◽  
Hadron Collider ◽  
Precise Determination ◽  
Proton Proton ◽  
Proton Collisions ◽  
Lhcb Detector ◽  
Proton Proton Collisions

AbstractMesons comprising a beauty quark and strange quark can oscillate between particle ($${B}_{\mathrm{s}}^{0}$$ B s 0 ) and antiparticle ($${\overline{B}}_{\mathrm{s}}^{0}$$ B ¯ s 0 ) flavour eigenstates, with a frequency given by the mass difference between heavy and light mass eigenstates, Δms. Here we present a measurement of Δms using $${B}_{\mathrm{s}}^{0}\to {D}_{\mathrm{s}}^{-}$$ B s 0 → D s − π+ decays produced in proton–proton collisions collected with the LHCb detector at the Large Hadron Collider. The oscillation frequency is found to be Δms = 17.7683 ± 0.0051 ± 0.0032 ps−1, where the first uncertainty is statistical and the second is systematic. This measurement improves on the current Δms precision by a factor of two. We combine this result with previous LHCb measurements to determine Δms = 17.7656 ± 0.0057 ps−1, which is the legacy measurement of the original LHCb detector.

scholarly journals Timepix3 Luminosity Determination of 13 TeV Proton-Proton Collisions at the ATLAS Experiment

2020 ◽  
Vol 225 ◽  
pp. 01002
Author(s):  
Andreé Sopczak
Keyword(s):  
Simple Model ◽  
Number Of Clusters ◽  
Proton Proton ◽  
Proton Collisions ◽  
Atlas Experiment ◽  
Long Term Stability ◽  
Counting Methods ◽  
Proton Proton Collisions

Medipix and Timepix devices, installed in the ATLAS cavern at the LHC, have provided valuable complementary luminosity information. Results are presented from measurements with Timepix3 (TPX3) detectors. In contrast with previously employed frame-based data acquisition, the TPX3 detector remains active continuously, sending information on pixel hits as they occur. Hit- and cluster-counting methods were used for the luminosity determination of the LHC protonproton collisions. The LHC luminosity versus time is determined using these two methods and fitted to a simple model, which incorporates luminosity reduction from single bunch and beam-beam interactions. The precision of the luminosity determination could be improved by counting the number of clusters, instead of just pixel hits. The internal precision and long-term stability of the TPX3 luminosity measurement are below 0.5%. TPX3, owing to its 1.56 ns time-tagging, is able to resolve the time structure of the luminosity due to the collisions of individual proton bunches when integrated over an LHC fill.

scholarly journals “Perfecting” pure shift HSQC: full homodecoupling for accurate and precise determination of heteronuclear couplings

2014 ◽  
Vol 50 (99) ◽  
pp. 15702-15705 ◽  
Author(s):  
L. Kaltschnee ◽  
A. Kolmer ◽  
I. Timári ◽  
V. Schmidts ◽  
R. W. Adams ◽  
...  
Keyword(s):  
High Precision ◽  
Precise Determination ◽  
Proton Proton

Full suppression of proton–proton couplings in pure shift HSQC spectra simplifies their analysis, as demonstrated for high precision RDC measurements.

scholarly journals On the precise determination of the Tsallis parameters in proton–proton collisions at LHC energies

2018 ◽  
Vol 45 (5) ◽  
pp. 055001 ◽  
Author(s):  
T Bhattacharyya ◽  
J Cleymans ◽  
L Marques ◽  
S Mogliacci ◽  
M W Paradza
Keyword(s):  
Precise Determination ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

scholarly journals Simultaneous determination of CKM angle γ and charm mixing parameters

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
◽  
R. Aaij ◽  
A. S. W. Abdelmotteleb ◽  
C. Abellán Beteta ◽  
F. Abudinén ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Precise Determination ◽  
Unitarity Triangle ◽  
Single Experiment ◽  
Mixing Parameters ◽  
Mixing Parameter ◽  
Lhcb Detector ◽  
First Time ◽  
Charm Mixing

Abstract A combination of measurements sensitive to the CP violation angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle and to the charm mixing parameters that describe oscillations between D0 and $$ \overline{D} $$ D ¯ 0 mesons is performed. Results from the charm and beauty sectors, based on data collected with the LHCb detector at CERN’s Large Hadron Collider, are combined for the first time. This method provides an improvement on the precision of the charm mixing parameter y by a factor of two with respect to the current world average. The charm mixing parameters are determined to be $$ x=\left({0.400}_{-0.053}^{+0.052}\right)\% $$ x = 0.400 − 0.053 + 0.052 % and y = $$ \left({0.630}_{-0.030}^{+0.033}\right)\% $$ 0.630 − 0.030 + 0.033 % . The angle γ is found to be γ = $$ \left({65.4}_{-4.2}^{+3.8}\right){}^{\circ} $$ 65.4 − 4.2 + 3.8 ° and is the most precise determination from a single experiment.

Two-field-NOESY for precise determination of proton–proton distances and correlation times

1999 ◽  
Vol 111 (17) ◽  
pp. 8253-8254 ◽  
Author(s):  
Xi-An Mao ◽  
Tao Zhang ◽  
Matthias Baur ◽  
Horst Kessler
Keyword(s):  
Precise Determination ◽  
Correlation Times ◽  
Proton Proton
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