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Title: Background estimator for jet studies in p + p and A + A collisions

Abstract

Experimentally, jet physics studies face an unavoidable task: distinguishing, at the detector level, the particles produced in the hard partonic scattering from the ones created in unrelated soft processes such as pileup interactions in high-luminosity proton-proton scattering or the underlying event in heavy-ion collisions. The fluctuating nature of the background constitutes the main source of uncertainty for any subtraction algorithm. Aiming at mitigating the effect of such fluctuations, we present a new method to estimate the background contribution to the transverse momentum on a jet-by-jet basis. Our approach is based on estimating the median background momentum density stored above a p T-cut applied at the constituent level and an experimentally accessible correction term related to the signal contribution below the cut. This allows to trade part of the uncertainty due to background contamination for that of the signal below the cut, similarly to the SoftKiller method. We propose to reduce the fluctuations of the latter by exploiting intrinsic correlations among the soft and hard sectors generated in the branching process of QCD jets. Our data-driven approach is tested against pythia8 and jewel dijet events embedded in minimum bias events and thermal background, respectively, and compared to the area-median and SoftKillermore » methods. The main result of this study is a ~5%-35% improvement on the resolution of the reconstructed jet p T compared to previous methods in both high-luminosity proton-proton and heavy-ion collisions.« less

Authors:
 [1];  [1];  [2]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Vanderbilt Univ., Nashville, TN (United States); Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN Research Center; Univ. of Utrecht (Netherlands)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1579431
Alternate Identifier(s):
OSTI ID: 1583115
Report Number(s):
BNL-213518-2020-JAAM
Journal ID: ISSN 2470-0010; PRVDAQ
Grant/Contract Number:  
SC0012704
Resource Type:
Published Article
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 100; Journal Issue: 11; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Mehtar-Tani, Yacine, Soto-Ontoso, Alba, and Verweij, Marta. Background estimator for jet studies in p+p and A+A collisions. United States: N. p., 2019. Web. doi:10.1103/PhysRevD.100.114023.
Mehtar-Tani, Yacine, Soto-Ontoso, Alba, & Verweij, Marta. Background estimator for jet studies in p+p and A+A collisions. United States. doi:10.1103/PhysRevD.100.114023.
Mehtar-Tani, Yacine, Soto-Ontoso, Alba, and Verweij, Marta. Fri . "Background estimator for jet studies in p+p and A+A collisions". United States. doi:10.1103/PhysRevD.100.114023.
@article{osti_1579431,
title = {Background estimator for jet studies in p+p and A+A collisions},
author = {Mehtar-Tani, Yacine and Soto-Ontoso, Alba and Verweij, Marta},
abstractNote = {Experimentally, jet physics studies face an unavoidable task: distinguishing, at the detector level, the particles produced in the hard partonic scattering from the ones created in unrelated soft processes such as pileup interactions in high-luminosity proton-proton scattering or the underlying event in heavy-ion collisions. The fluctuating nature of the background constitutes the main source of uncertainty for any subtraction algorithm. Aiming at mitigating the effect of such fluctuations, we present a new method to estimate the background contribution to the transverse momentum on a jet-by-jet basis. Our approach is based on estimating the median background momentum density stored above a pT-cut applied at the constituent level and an experimentally accessible correction term related to the signal contribution below the cut. This allows to trade part of the uncertainty due to background contamination for that of the signal below the cut, similarly to the SoftKiller method. We propose to reduce the fluctuations of the latter by exploiting intrinsic correlations among the soft and hard sectors generated in the branching process of QCD jets. Our data-driven approach is tested against pythia8 and jewel dijet events embedded in minimum bias events and thermal background, respectively, and compared to the area-median and SoftKiller methods. The main result of this study is a ~5%-35% improvement on the resolution of the reconstructed jet pT compared to previous methods in both high-luminosity proton-proton and heavy-ion collisions.},
doi = {10.1103/PhysRevD.100.114023},
journal = {Physical Review D},
number = 11,
volume = 100,
place = {United States},
year = {2019},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
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DOI: 10.1103/PhysRevD.100.114023

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