اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDouble parton scattering in four-jet events in pp collisions at 7 TeV with the ATLAS experiment at the LHC
133
0
0.0
(
0
)
تأليف
Iftach Sadeh
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The dijet double-differential cross section is measured as a function of the dijet invariant mass, using data taken during 2010 and during 2011 with the ATLAS experiment at the LHC, with a center-of-mass energy of 7 TeV. The measurements are sensitive to invariant masses between 70 GeV and 4.27 TeV with center-of-mass jet rapidities up to 3.5. A novel technique to correct jets for pile-up (additional proton-proton collisions) in the 2011 data is developed and subsequently used in the measurement. The data are found to be consistent with fixed-order NLO pQCD predictions provided by NLOJET++. The results constitute a stringent test of pQCD, in an energy regime previously unexplored. The dijet analysis is a confidence building step for the extraction of the signal of hard double parton scattering (DPS) in four-jet events, and subsequent extraction of the effective overlap area between the interacting protons, expressed in terms of the variable, sigma(eff). The measurement of DPS is performed using the 2010 ATLAS data. The rate of DPS events is estimated using a neural network. A clear signal is observed, under the assumption that the DPS signal can be represented by a random combination of exclusive dijet production. The fraction of DPS candidate events is determined to be f(DPS) = 0.081 +- 0.004 (stat.) +0.025-0.014 (syst.) in the analyzed phase-space of four-jet topologies. Combined with the measurement of the dijet and four-jet cross sections in the appropriate phase-space regions, the effective cross section is found to be sigma(eff) = 16.0 +0.5-0.8 (stat.) +1.9-3.5 (syst.) mb. This result is consistent within the quoted uncertainties with previous measurements of sigma(eff) at center-of-mass energies between 63 GeV and 7 TeV, using several final states.
قيم البحث
اقرأ أيضاً
We present predictions for the double parton scattering (DPS) four-jet production cross sections in $pA$ collisions at the LHC. Relying on the experimental capabilities to correlate centrality with impact parameter $B$ of the proton-nucleus collision
, we discuss a strategy to extract the double parton scattering contributions in $pA$ collisions, which gives direct access to double parton distribution in the nucleon. We show that the production cross sections via DPS of four jets, out of which two may be light- or heavy-quark jets, are large enough to allow the method to be used already with data accumulated in 2016 $pA$ run.
Associated production of bottomonia and open charm hadrons in $pp$ collisions at $sqrt{s}=7$ and $8$TeV is observed using data corresponding to an integrated luminosity of 3$fb^{-1}$ accumulated with the LHCb detector. The observation of five combina
tions, $Upsilon(1S)D^0$, $Upsilon(2S)D^0$, $Upsilon(1S)D^+$, $Upsilon(2S)D^+$ and $Upsilon(1S)D^+_{s}$, is reported. Production cross-sections are measured for $Upsilon(1S)D^0$ and $Upsilon(1S)D^+$ pairs in the forward region. The measured cross-sections and the differential distributions indicate the dominance of double parton scattering as the main production mechanism. This allows a precise measurement of the effective cross-section for double parton scattering.
A measurement of the $Z(rightarrowmu^+mu^-)$+jet production cross-section in $pp$ collisions at a centre-of-mass energy $sqrt{s} = 7$ TeV is presented. The analysis is based on an integrated luminosity of $1.0,text{fb}^{-1}$ recorded by the LHCb expe
riment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction ($2.0<eta<4.5$). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction.
Hadrons measured in proton-proton collisions at sqrt(s) = 0.9 and 7 TeV with the ALICE detector have been identified using various techniques: the specific energy loss and the time-of flight information for charged pions, kaons and protons, the displ
aced vertex resulting from their weak decay for K0, Lambda and Xi and the kink topology of decaying charged kaons. These various particle identification tools give the best separation at different momentum ranges and the results are combined to obtain spectra from pt = 100 MeV/c to 2.5 GeV/c. This allows to extract total yields. In detail we discuss the K/pi ratio together with previous measurements and we show a fit using a statistical approach.
The measurement of the inclusive cross section for Wgamma production is presented based on 36/ pb of data acquired with the CMS detector from 7 TeV LHC collisions in 2010. Comparisons are made with the predictions of the standard model. The W bosons
are identified through their leptonic decays to electrons and muons. The Wgamma cross section is sensitive to anomalous triple-gauge couplings and hence this measurement probes physics beyond the standard model.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
