scholarly journals In-medium transverse momentum broadening effects ondi-jet observables

2021 ◽  
Author(s):  
Martin Rohrmoser ◽  
Krzysztof Kutak ◽  
Andreas Van Hameren ◽  
Wiesław Płaczek ◽  
Konrad Tywoniuk
Keyword(s):  
Transverse Momentum ◽  
Jet Observables

scholarly journals Deep learning jet modifications in heavy-ion collisions

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yi-Lun Du ◽  
Daniel Pablos ◽  
Konrad Tywoniuk
Keyword(s):  
Deep Learning ◽  
Transverse Momentum ◽  
Energy Loss ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Loss Ratio ◽  
Ion Collisions ◽  
Learning Techniques ◽  
Jet Observables ◽  
The Impact

Abstract Jet interactions in a hot QCD medium created in heavy-ion collisions are conventionally assessed by measuring the modification of the distributions of jet observables with respect to the proton-proton baseline. However, the steeply falling production spectrum introduces a strong bias toward small energy losses that obfuscates a direct interpretation of the impact of medium effects in the measured jet ensemble. Modern machine learning techniques offer the potential to tackle this issue on a jet-by-jet basis. In this paper, we employ a convolutional neural network (CNN) to diagnose such modifications from jet images where the training and validation is performed using the hybrid strong/weak coupling model. By analyzing measured jets in heavy-ion collisions, we extract the original jet transverse momentum, i.e., the transverse momentum of an identical jet that did not pass through a medium, in terms of an energy loss ratio. Despite many sources of fluctuations, we achieve good performance and put emphasis on the interpretability of our results. We observe that the angular distribution of soft particles in the jet cone and their relative contribution to the total jet energy contain significant discriminating power, which can be exploited to tailor observables that provide a good estimate of the energy loss ratio. With a well-predicted energy loss ratio, we study a set of jet observables to estimate their sensitivity to bias effects and reveal their medium modifications when compared to a more equivalent jet population, i.e., a set of jets with similar initial energy. Finally, we also show the potential of deep learning techniques in the analysis of the geometrical aspects of jet quenching such as the in-medium traversed length or the position of the hard scattering in the transverse plane, opening up new possibilities for tomographic studies.

HIGH TRANSVERSE MOMENTUM PROCESSES

1973 ◽  
Vol 34 (C1) ◽  
pp. C1-385-C1-399 ◽  
Author(s):  
J. D. BJORKEN
Keyword(s):  
Transverse Momentum ◽  
High Transverse Momentum

scholarly journals Search for new phenomena in final states with b-jets and missing transverse momentum in $$ \sqrt{\mathrm{s}} $$ = 13 TeV pp collisions with the ATLAS detector

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Atlas Detector ◽  
Final States ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
The Standard Model ◽  
Proton Data ◽  
Identification Techniques ◽  
New Phenomena

Abstract The results of a search for new phenomena in final states with b-jets and missing transverse momentum using 139 fb−1 of proton-proton data collected at a centre-of-mass energy $$ \sqrt{s} $$ s = 13 TeV by the ATLAS detector at the LHC are reported. The analysis targets final states produced by the decay of a pair-produced supersymmetric bottom squark into a bottom quark and a stable neutralino. The analysis also seeks evidence for models of pair production of dark matter particles produced through the decay of a generic scalar or pseudoscalar mediator state in association with a pair of bottom quarks, and models of pair production of scalar third-generation down-type leptoquarks. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered by the analysis. Bottom squark masses below 1270 GeV are excluded at 95% confidence level if the neutralino is massless. In the case of nearly mass-degenerate bottom squarks and neutralinos, the use of dedicated secondary-vertex identification techniques permits the exclusion of bottom squarks with masses up to 660 GeV for mass splittings between the squark and the neutralino of 10 GeV. These limits extend substantially beyond the regions of parameter space excluded by similar ATLAS searches performed previously.

ResBos and ePump Analysis on ATLAS 8TeV Z Boson Transverse Momentum Distributions

2021 ◽  
Author(s):  
Qaynar Jandaolet ◽  
Alim Ablat ◽  
Pazilet Obul ◽  
Reyima Rashidin ◽  
Ibrahim Sitiwaldi
Keyword(s):  
Transverse Momentum ◽  
Z Boson ◽  
Momentum Distributions

scholarly journals Skewness of mean transverse momentum fluctuations in heavy-ion collisions

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
Giuliano Giacalone ◽  
Fernando G. Gardim ◽  
Jacquelyn Noronha-Hostler ◽  
Jean-Yves Ollitrault
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Ion Collisions
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