Dielectron production in proton-proton collisions at root s=7 TeV

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F18%3A00494425" target="_blank" >RIV/61389005:_____/18:00494425 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/18:00494425 RIV/68407700:21340/18:00328330

Výsledek na webu

<a href="http://dx.doi.org/10.1007/JHEP09(2018)064" target="_blank" >http://dx.doi.org/10.1007/JHEP09(2018)064</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/JHEP09(2018)064" target="_blank" >10.1007/JHEP09(2018)064</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Dielectron production in proton-proton collisions at root s=7 TeV

Popis výsledku v původním jazyce

The first measurement of e(+)e(-) pair production at mid-rapidity (vertical bar eta vertical bar(e) < 0.8) in pp collisions at root s = 7TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (m(ee )< 3.3 GeV/c(2)), the pair transverse momentum (p(T,ee) < 8 GeV/c), and the pair transverse impact parameter (DCA(ee)), i.e., the average distance of closest approach of the reconstructed electron and positron tracks to the collision vertex, normalised to its resolution. The results are compared with the expectations from a cocktail of known hadronic sources and are well described when PYTHIA is used to generate the heavy-flavour contributions. In the low-mass region (0.14 < m(ee) < 1.1 GeV/c(2)), prompt and non-prompt e(+)e(-) sources can be separated via the DCA(ee). In the intermediate-mass region (1.1 < m(ee) < 2.7 GeV/c(2)), a double-differential fit to the data in m(ee) and p(T,ee) and a fit of the DCA(ee) distribution allow the total cc and bb cross sections to be extracted. Two different event generators, PYTHIA and POWHEG, can reproduce the shape of the two-dimensional m(ee) and p(T,ee) spectra, as well as the shape , of the DCA(ee) distribution, reasonably well. However, differences in the c (c) over bar and b (b) over bar cross sections are observed when using the generators to extrapolate to full phase space. Finally, the ratio of inclusive to decay photons is studied via the measurement of virtual direct photons in the transverse-momentum range 1 < p(T) < 8 GeV/c. This is found to be unity within the statistical and systematic uncertainties and consistent with expectations from next-to-leading order perturbative quantum chromodynamic calculations.

Název v anglickém jazyce

Dielectron production in proton-proton collisions at root s=7 TeV

Popis výsledku anglicky

The first measurement of e(+)e(-) pair production at mid-rapidity (vertical bar eta vertical bar(e) < 0.8) in pp collisions at root s = 7TeV with ALICE at the LHC is presented. The dielectron production is studied as a function of the invariant mass (m(ee )< 3.3 GeV/c(2)), the pair transverse momentum (p(T,ee) < 8 GeV/c), and the pair transverse impact parameter (DCA(ee)), i.e., the average distance of closest approach of the reconstructed electron and positron tracks to the collision vertex, normalised to its resolution. The results are compared with the expectations from a cocktail of known hadronic sources and are well described when PYTHIA is used to generate the heavy-flavour contributions. In the low-mass region (0.14 < m(ee) < 1.1 GeV/c(2)), prompt and non-prompt e(+)e(-) sources can be separated via the DCA(ee). In the intermediate-mass region (1.1 < m(ee) < 2.7 GeV/c(2)), a double-differential fit to the data in m(ee) and p(T,ee) and a fit of the DCA(ee) distribution allow the total cc and bb cross sections to be extracted. Two different event generators, PYTHIA and POWHEG, can reproduce the shape of the two-dimensional m(ee) and p(T,ee) spectra, as well as the shape , of the DCA(ee) distribution, reasonably well. However, differences in the c (c) over bar and b (b) over bar cross sections are observed when using the generators to extrapolate to full phase space. Finally, the ratio of inclusive to decay photons is studied via the measurement of virtual direct photons in the transverse-momentum range 1 < p(T) < 8 GeV/c. This is found to be unity within the statistical and systematic uncertainties and consistent with expectations from next-to-leading order perturbative quantum chromodynamic calculations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10304 - Nuclear physics

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of High Energy Physics

ISSN

1029-8479

e-ISSN

—

Svazek periodika

2018

Číslo periodika v rámci svazku

9

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

47

Strana od-do

—

Kód UT WoS článku

000444678800007

EID výsledku v databázi Scopus

2-s2.0-85053272489