scholarly journals Determination of αs in NNLO QCD using H1 jet cross section measurements

2019 ◽  
Vol 206 ◽  
pp. 01002
Author(s):  
Vladimir Chekelian
Keyword(s):  
Strong Coupling ◽  
Cross Section ◽  
Cross Sections ◽  
Neutral Current ◽  
Distribution Functions ◽  
Boson Mass ◽  
Parton Distribution Functions ◽  
Inclusive Jet ◽  
Using Data ◽  
Jet Cross Sections

Measurements of jet cross sections in neutral current deep-inelastic scattering (NC DIS) using data taken with the H1 detector at HERA are accomplished by the precision measurement of double-differential inclusive jet, dijet and trijet cross sections at low photon virtualities 5.5 < Q2 < 80 GeV2, and by extending previous inclusive jet measurements in the range 150 < Q2 < 15000 GeV2 to low transverse jet momenta 5 < PT < 7 GeV. The strong coupling constant at the Z-boson mass, αs(mZ), is determined in next-to-next-to-leading order (NNLO) QCD using H1 inclusive jet and dijet cross section measurements. Complementary, αs(mZ) is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with the QCD expectations.

Accurate prediction of the Drell-Yan φ∗ η distribution in wide dilepton mass and rapidity ranges in pp collisions through NNLO+N3LL

2021 ◽  
Author(s):  
Kadir Ocalan
Keyword(s):  
Cross Sections ◽  
Good Description ◽  
Neutral Current ◽  
Mass Range ◽  
Theoretical Description ◽  
Distribution Functions ◽  
Boson Mass ◽  
Pp Collisions ◽  
Parton Distribution Functions ◽  
Central Detector

Abstract This paper presents high-accuracy predictions for the differential cross sections as a function of the key observable φ*η of the neutral-current Drell-Yan (DY) dilepton production in proton-proton (pp) collisions. The differential distributions for the φ*η are presented by using the state-of-the-art predictions from the combined calculations of fixed-order perturbative QCD corrections at next-to-next-to-leading order (NNLO) accuracy and resummation of large logarithmic terms at next-to-next-to-leading logarithmic (NNLL) and next-to-NNLL (N3LL) accuracies, i.e., NNLO+NNLL and NNLO+N3LL, respectively. The predicted distributions are reported for a thorough set of the DY dilepton invariant mass mll ranges, spanning a wide kinematic region of 50 < mll< 1000 GeV both near and away from the Z-boson mass peak, and rapidity yll ranges in the central detector acceptance region of |yll| < 2.4. The differential φ*η distributions in the wide mll and yll ranges offer stringent tests to assess the reliability of the predictions, where the mll and yll are closely correlated with the parton distribution functions (PDFs) of the incoming partons. The merged predictions through NNLO+N3LL are observed to provide good description of the 13 TeV pp collision data for the φ*η (including the dilepton transverse momentum pll T as well) distributions in almost the entire mll and yll ranges, apart from the intermediate- to high-φ*η region in the lowest mass range 50–76 GeV which is assessed to constitute a challenge for the presented predictions. The merged predictions at NNLO+N3LL are also reported at 14 TeV for the upcoming high-luminosity running era of the LHC, in which increasing amount of data is expected to require more accurate and precise theoretical description. The most recent PDF models MSHT20 and CT18 are tested for the first time in addition to the NNPDF3.1 exploiting the merged φ*η predictions.

QCD JETS AT HERA I.: O(αs) RADIATIVE CORRECTIONS TO ELECTROWEAK CROSS SECTIONS AND JET RATES

1989 ◽  
Vol 04 (07) ◽  
pp. 1781-1825 ◽  
Author(s):  
JÜRGEN G. KÖRNER ◽  
ERWIN MIRKES ◽  
GERHARD A. SCHULER
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Neutral Current ◽  
High Energy ◽  
Coupling Constant ◽  
Bjorken Scaling ◽  
Born Cross Section ◽  
Wide Range ◽  
Lepton Polarization ◽  
Jet Cross Sections

We present the complete O(αs) corrections to the electroweak cross sections of both neutral current and charged current deep inelastic e±p scattering including lepton polarization effects. Changes in the cross section due to the inclusion of next-to-leading-log (NLL) effects are parametrized by K factors, which are defined as the ratio of the NLL O(αs) cross sections and the Born cross section. Using the standard redefinition scheme of the parton densities, we find that the K factors deviate substantially from unity for small values of the Bjorken-Scaling variable x. We also elaborate on problems that arise when defining jet cross sections in ep scattering and present numerical results for the O(αs) 3-jet and 2-jet rates. We observe that the Q2-dependence of the 3-jet rate is dominated by the running strong coupling constant αs(Q2) allowing for its determination over a wide range in Q2 at high energy ep colliders.

scholarly journals Electroweak measurements from W, Z and photon final states

2014 ◽  
Vol 31 ◽  
pp. 1460276
Author(s):  
Hang Yin ◽  
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Z Boson ◽  
W Boson ◽  
Charge Asymmetry ◽  
Distribution Functions ◽  
Boson Mass ◽  
Electroweak Theory ◽  
Final States ◽  
Parton Distribution Functions

We present the most recent precision electroweak measurements of single W and Z boson cross section and properties from the LHC and Tevatron colliders, analyzing data collected by ATLAS, CDF, CMS, D0, and LHCb detectors. The results include the measurement of the single W and Z boson cross section at LHC, the differential cross section measurements, the measurement of W boson mass, the measurement of W and Z charge asymmetry. These measurements provide precision tests on the electroweak theory, high order predictions and the information can be used to constraint parton distribution functions.

scholarly journals Measurement of the cross-section and charge asymmetry of W bosons produced in proton–proton collisions at $$\sqrt{s}=8~\text {TeV}$$ with the ATLAS detector

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Charge Asymmetry ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Proton Collisions ◽  
The Cross ◽  
Proton Proton Collisions ◽  
Integrated Luminosity

Abstract This paper presents measurements of the $$W^+ \rightarrow \mu ^+\nu $$W+→μ+ν and $$W^- \rightarrow \mu ^-\nu $$W-→μ-ν cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton–proton collisions at a centre-of-mass energy of 8 $$\text {TeV}$$TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of $$20.2~\text{ fb }^{-1}$$20.2fb-1. The precision of the cross-section measurements varies between 0.8 and 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.

scholarly journals Inclusive jet cross sections in the Breit frame in neutral current deep inelastic scattering at HERA and determination of αs

2002 ◽  
Vol 547 (3-4) ◽  
pp. 164-180 ◽  
Author(s):  
S. Chekanov ◽  
D. Krakauer ◽  
S. Magill ◽  
B. Musgrave ◽  
J. Repond ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Cross Sections ◽  
Neutral Current ◽  
Inclusive Jet ◽  
Jet Cross Sections

scholarly journals JET CROSS-SECTION MEASUREMENTS IN CMS

2013 ◽  
Vol 28 (20) ◽  
pp. 1330030 ◽  
Author(s):  
SANMAY GANGULY ◽  
MONORANJAN GUCHAIT
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Mass Measurement ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Order Theory ◽  
Distribution Functions ◽  
Dijet Mass ◽  
Inclusive Jet ◽  
Integrated Luminosity

The Large Hadron Collider experiment has successfully completed data taking at center-of-mass energy 7 TeV in 2011 and very recently for 8 TeV. Measurements of cross-sections predicted by the standard model were the main tasks in the beginning. The inclusive jet cross-section and dijet mass measurement are already done at 7 TeV energy by Compact Muon Solenoid (CMS) detector with integrated luminosity 5 fb-1. In these measurement, one needs to understand and measure precisely the kinematic properties of jets which involve many theoretical and experimental issues. The goal of this paper is to discuss all these issues including jet measurements in CMS and subsequently review the inclusive jet cross-section and dijet mass measurement in CMS at 7 TeV with integrated luminosity 5 fb-1. The measurements, after unfolding the data, are also compared with the next-to-leading-order theory predictions, corrected for the nonperturbative effects, for five different sets of parton distribution functions. It is observed that the measurements, for both cases, agree with the theory prediction within ~8–10% depending on transverse momentum (pT) and dijet invariant mass (Mjj) of jets.

scholarly journals Applications of pT-xR Variables in Describing Inclusive Cross Sections at the LHC

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 196
Author(s):  
Frank Taylor
Keyword(s):  
Cross Sections ◽  
Single Particle ◽  
Power Laws ◽  
Inclusive Cross Section ◽  
Heavy Ion ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Heavy Ion Physics ◽  
Inclusive Jets ◽  
Jet Cross Sections

Invariant inclusive single-particle/jet cross sections in p–p collisions can be factorized in terms of two separable dependences, a [pT−s] sector and an [xR−pT−s] sector. Here, we extend our earlier work by analyzing more extensive data to explore various s-dependent attributes and other systematics of inclusive jet, photon and single particle reactions. Approximate power laws in s,pT and xR are found. Physical arguments are given which relate observations to the underlying physics of parton–parton hard scattering and the parton distribution functions in the proton. We show that the A(s,pT) function, introduced in our earlier publication to describe the pT dependence of the inclusive cross section, is directly related to the underlying hard parton–parton scattering for jet production, with little influence from soft physics. In addition to the A-function, we introduce another function, the F(s,xR) function that obeys radial scaling for inclusive jets and offers another test of the underlying parton physics. An application to heavy ion physics is given, where we use our variables to determine the transparency of cold nuclear matter to penetrating heavy mesons through the lead nucleus.

scholarly journals nNNPDF2.0: quark flavor separation in nuclei from LHC data

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Rabah Abdul Khalek ◽  
Jacob J. Ethier ◽  
Juan Rojo ◽  
Gijs van Weelden
Keyword(s):  
Cross Sections ◽  
Good Description ◽  
Neutral Current ◽  
High Energy ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Nuclear Dynamics ◽  
Monte Carlo Techniques ◽  
Rapidity Distributions ◽  
Nuclear Modifications

Abstract We present a model-independent determination of the nuclear parton distribution functions (nPDFs) using machine learning methods and Monte Carlo techniques based on the NNPDF framework. The neutral-current deep-inelastic nuclear structure functions used in our previous analysis, nNNPDF1.0, are complemented by inclusive and charm-tagged cross-sections from charged-current scattering. Furthermore, we include all available measurements of W and Z leptonic rapidity distributions in proton-lead collisions from ATLAS and CMS at $$ \sqrt{s} $$ s = 5.02 TeV and 8.16 TeV. The resulting nPDF determination, nNNPDF2.0, achieves a good description of all datasets. In addition to quantifying the nuclear modifications affecting individual quarks and antiquarks, we examine the implications for strangeness, assess the role that the momentum and valence sum rules play in nPDF extractions, and present predictions for representative phenomenological applications. Our results, made available via the LHAPDF library, highlight the potential of high-energy collider measurements to probe nuclear dynamics in a robust manner.

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