We provide an update on QCD predictions for top-quark pair production close to threshold including bound state effects at the Large Hadron Collider. We compute the top-quark pair invariant mass distribution <math altimg='si1.svg'><mi>d</mi><mi>&#963;</mi><mo stretchy='false'>/</mo><mi>d</mi><msub><mrow><mi>M</mi></mrow><mrow><mi>t</mi><mover accent='true'><mrow><mi>t</mi></mrow><mrow><mo stretchy='false'>&#175;</mo></mrow></mover></mrow></msub></math>, including Coulomb resummation for bound-state effects, as well as threshold resummation for emissions of soft and collinear gluons. We discuss uncertainty estimates and present a proposal for the use of these predictions in experimental analyses.

Switzerland

Germany

M.V. Garzelli

G. Limatola

S.O. Moch

M. Steinhauser

O. Zenaiev

Updated predictions for toponium production at the LHC

We study the impact of state-of-the-art top-quark data collected at the large hadron collider on parton distribution functions (PDFs). Following the ABMP methodology, the fit extracts simultaneously proton PDFs, the strong coupling $$\alpha _s(M_Z)$$ and heavy-quark masses at next-to-next-to-leading order (NNLO) accuracy in QCD. It includes recent high-statistics data on absolute total inclusive cross sections for $$t\bar{t}+X$$ , the sum of $$(t + X)$$ and $$(\bar{t} + X)$$ hadroproduction, and normalized inclusive data double-differential in the invariant mass and rapidity of the $$t\bar{t}$$ pair at $$\sqrt{S}=13$$ TeV. The gluon PDF at large and the top-quark mass value derived from these data are well compatible with the previous ABMP16 results, but with significantly smaller uncertainties, reduced by up to a factor of two. At NNLO in QCD we obtain for the strong coupling the value $$\alpha _s^{(n_f=5)}(M_Z)= 0.1150 \pm 0.0009$$ and for the top-quark mass in the $${\overline{\text{ MS }}}$$ -scheme $$m_t(m_t) = 160.6 \pm 0.6$$ GeV, corresponding to $$m_t^\textrm{pole} = 170.2 \pm 0.7$$ GeV in the on-shell scheme. The new fit, dubbed ABMPtt, is publicly released in grids in LHAPDF format.

S. Alekhin

M. Garzelli

NNLO PDFs driven by top-quark data

We extract the top-quark mass value in the on-shell renormalization scheme from the comparison of theoretical predictions for pp →   <math> <mi>t</mi> <mover> <mi>t</mi> <mo>¯</mo> </mover> </math>  $$ t\overline{t} $$  + X at next-to-next-to-leading order (NNLO) QCD accuracy with experimental data collected by the ATLAS and CMS collaborations for absolute total, normalized single-differential and double-differential cross-sections during Run 1, Run 2 and the ongoing Run 3 at the Large Hadron Collider (LHC). For the theory computations of heavy-quark pair-production we use the MATRIX framework, interfaced to PineAPPL for the generation of grids of theory predictions, which can be efficiently used a-posteriori during the fit, performed within xFitter. We take several state-of-the-art parton distribution functions (PDFs) as input for the fit and evaluate their associated uncertainties, as well as the uncertainties arising from renormalization and factorization scale variation. Fit uncertainties related to the datasets are also part of the extracted uncertainty of the top-quark mass and turn out to be of similar size as the combined scale and PDF uncertainty. Fit results from different PDF sets agree among each other within 1σ uncertainty, whereas some datasets related to   <math> <mi>t</mi> <mover> <mi>t</mi> <mo>¯</mo> </mover> </math>  $$ t\overline{t} $$  decay in different channels (dileptonic vs. semileptonic) point towards top-quark mass values in slight tension among each other, although still compatible within 2.5 σ accuracy. Our results are compatible with the PDG 2022 top-quark pole-mass value. Our work opens the road towards more complex simultaneous NNLO fits of PDFs, the strong coupling α  s (M  Z ) and the top-quark mass, using the currently most precise experimental data on   <math> <mi>t</mi> <mover> <mi>t</mi> <mo>¯</mo> </mover> </math>  $$ t\overline{t} $$  + X total and multi-differential cross sections from the LHC.

J. Mazzitelli

Top-quark pole mass extraction at NNLO accuracy, from total, single- and double-differential cross sections for   <math> <mi>t</mi> <mover> <mi>t</mi> <mo>¯</mo> </mover> </math>  $$ t\overline{t} $$  + X production at the LHC

We evaluate the impact of recent SeaQuest (FNAL-E906 experiment) data on dimuon production in proton-deuteron and proton-proton collisions on parton distribution functions (PDFs). We find these data in a good agreement with the QCD predictions based on PDFs fitted to the Tevatron and LHC data on forward production of W and Z bosons. As a basis for this study we use the ABMP16 PDF fits and show that they turn out to be compatible with the SeaQuest data, and that these data have constraining power, allowing to reduce the uncertainties on the isospin asymmetry of the light-sea-quark distribution at large longitudinal momentum fraction x. We discuss the nuclear corrections needed to describe the deuteron and show that they affect the theoretical description of the proton-deuteron Drell–Yan cross section at the level of  $$\mathcal {O}(0.5{-}1)$$  <math> <mrow> <mi>O</mi> <mo>(</mo> <mn>0.5</mn> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> </math>  %. We also comment on the compatibility of the SeaQuest results with other state-of-the-art PDF fits and show that these data are in clear disagreement with models proposing an SU(3)-flavor symmetric quark sea. Finally, we perform a comparison between the second Mellin moments of the light-quark PDFs and recent results from various lattice QCD computations, which demonstrates good compatibility, albeit limited by the uncertainties inherent in current lattice QCD simulations.

Russia

S. Kulagin

Impact of SeaQuest data on PDF fits at large x

The impact of measurements of heavy-flavour production in deep inelastic scattering and in collisions on parton distribution functions is studied in a QCD analysis at next-to-leading order. Recent combined results of inclusive and heavy-flavour produc- tion cross sections in deep inelastic scattering at HERA are investigated together with heavy-flavour production measurements at the LHC. Differential cross sections of charm- and beauty-hadron production measured by the LHCb collaboration at the centre-of-mass energies of 5, 7 and 13 TeV as well as the recent measurements of the ALICE experiment at the centre-of-mass energies of 5 and 7 TeV are explored. These data impose additional constraints on the gluon and the sea-quark distributions at low partonic fractions of the proton momentum, down to 10 6 . The impact of the resulting parton distribution function in the predictions for the prompt atmospheric-neutrino fluxes is studied.

Italy

K. Lipka

United Kingdom

A. Cooper-Sarkar

United States

F. Olness

A. Geiser

G. Sigl

Improved constraints on parton distributions using LHCb, ALICE and HERA heavy-flavour measurements and implications for the predictions for prompt atmospheric-neutrino fluxes

The running of the top quark mass is experimentally investigated for the first time. The mass of the top quark in the modified minimal subtraction (<math><mover><mrow><mi>MS</mi></mrow><mo>‾</mo></mover></math>) renormalization scheme is extracted from a comparison of the differential top quark-antiquark (<math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mrow><mo>¯</mo></mrow></mover></math>) cross section as a function of the invariant mass of the <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mrow><mo>¯</mo></mrow></mover></math> system to next-to-leading-order theoretical predictions. The differential cross section is determined at the parton level by means of a maximum-likelihood fit to distributions of final-state observables. The analysis is performed using <math><mi>t</mi><mover><mrow><mi>t</mi></mrow><mrow><mo>¯</mo></mrow></mover></math> candidate events in the e$^{±}$ μ$^{∓}$ channel in proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by the CMS detector at the CERN LHC in 2016, corresponding to an integrated luminosity of 35.9<math><mspace width="0.2em"></mspace><msup><mrow><mtext>fb</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The extracted running is found to be compatible with the scale dependence predicted by the corresponding renormalization group equation. In this analysis, the running is probed up to a scale of the order of 1 TeV.

Armenia

A.M. Sirunyan

A. Tumasyan

Austria

W. Adam

F. Ambrogi

T. Bergauer

J. Brandstetter

M. Dragicevic

J. Erö

A. Escalante Del Valle

M. Flechl

R. Frühwirth

M. Jeitler

N. Krammer

I. Krätschmer

D. Liko

T. Madlener

I. Mikulec

N. Rad

J. Schieck

R. Schöfbeck

M. Spanring

D. Spitzbart

W. Waltenberger

C.E. Wulz

M. Zarucki

Belarus

V. Drugakov

V. Mossolov

J. Suarez Gonzalez

Belgium

M.R. Darwish

E.A. De Wolf

D. Di Croce

X. Janssen

A. Lelek

M. Pieters

H. Rejeb Sfar

H. Van Haevermaet

P. Van Mechelen

S. Van Putte

N. Van Remortel

F. Blekman

E.S. Bols

S.S. Chhibra

J. D'Hondt

J. De Clercq

D. Lontkovskyi

S. Lowette

I. Marchesini

S. Moortgat

Q. Python

K. Skovpen

S. Tavernier

W. Van Doninck

P. Van Mulders

D. Beghin

B. Bilin

H. Brun

B. Clerbaux

G. De Lentdecker

H. Delannoy

B. Dorney

L. Favart

A. Grebenyuk

A.K. Kalsi

A. Popov

N. Postiau

E. Starling

L. Thomas

C. Vander Velde

P. Vanlaer

D. Vannerom

T. Cornelis

D. Dobur

I. Khvastunov

M. Niedziela

C. Roskas

M. Tytgat

W. Verbeke

B. Vermassen

M. Vit

O. Bondu

G. Bruno

C. Caputo

P. David

C. Delaere

M. Delcourt

A. Giammanco

V. Lemaitre

J. Prisciandaro

A. Saggio

M. Vidal Marono

P. Vischia

J. Zobec

Brazil

F.L. Alves

G.A. Alves

G. Correia Silva

C. Hensel

A. Moraes

P. Rebello Teles

E. Belchior Batista Das Chagas

W. Carvalho

Running of the top quark mass from proton-proton collisions at

QCD in <math><mi>d</mi><mo>=</mo><mn>4</mn><mo>−</mo><mn>2</mn><mi>ϵ</mi></math> space-time dimensions possesses a nontrivial critical point and there are good reasons to expect that this theory restricted to the gauge-invariant subsector is conformally invariant. The subtlety is that the conformal symmetry of the Lagrangian is broken by the Faddeev-Popov quantization procedure. We study this problem by tracing carefully the contributions of gauge non-invariant operators in conformal Ward identities and prove that all such contributions cancel in the correlation functions of gauge-invariant operators. This result gives further support to the application of the conformal symmetry based methods in high-order QCD calculations.

V.M. Braun

A.N. Manashov

M. Strohmaier

Conformal symmetry of QCD in -dimensions

The impact of recent measurements of heavy-flavour production in deep inelastic ep scattering and in pp collisions on parton distribution functions is studied in a QCD analysis in the fixed-flavour number scheme at next-to-leading order. Differential cross sections of charm- and beauty-hadron production measured by LHCb are used together with inclusive and heavy-flavour production cross sections in deep inelastic scattering at HERA. The heavy-flavour data of the LHCb experiment impose additional constraints on the gluon and the sea-quark distributions at low partonic fractions x of the proton momentum, down to x∼5×10-6 . This kinematic range is currently not covered by other experimental data in perturbative QCD fits.

J. Blümlein

M. Guzzi

O. Kuprash

P. Nadolsky

R. Placakyte

K. Rabbertz

France

I. Schienbein

P. Starovoitov

Impact of heavy-flavour production cross sections measured by the LHCb experiment on parton distribution functions at low x