<p>The violation of the Lam-Tung relation in the high-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>p</mi><mi>T</mi><mrow><mo>ℓ</mo><mo>ℓ</mo></mrow></msubsup></math> region of the Drell-Yan process at the LHC presents a longstanding discrepancy with the standard model prediction at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msubsup><mi>α</mi><mi>s</mi><mn>3</mn></msubsup><mo stretchy="false">)</mo></math> accuracy. In this paper, we employed a model-independent analysis to investigate this phenomenon within the framework of the standard model effective field theory (SMEFT). Our findings revealed that the leading contributions from SMEFT to this violation appear at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><msup><mi mathvariant="normal">Λ</mi><mn>4</mn></msup></math> order with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msub><mi>α</mi><mi>s</mi></msub><mo stretchy="false">)</mo></math> accuracy in quantum chromodynamics (QCD) interaction. Notably, we demonstrated that the quadratic effect of dimension-6 dipole operators, associated with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson, dominates the breaking effects induced by various dimension-6 and dimension-8 operators. This provides a possible explanation for the observed discrepancy with the Standard Model predictions at the LHC. Furthermore, the breaking effects could also serve as a powerful tool for constraining <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math>-boson dipole interactions, highlighting their importance among potential sources of new physics in the Drell-Yan process.</p>

China

Xu Li

Bin Yan

United States

C.P. Yuan

Lam-Tung relation breaking in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson production as a probe of standard model effective field theory effects

<p>In this study, we investigate the impact of new Large Hadron Collider (LHC) inclusive jet and dijet measurements on parton distribution functions (PDFs) that describe the proton structure, with a particular focus on the gluon distribution at large momentum fraction, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math>, and the corresponding partonic luminosities. We assess constraints from these datasets using next-to-next-to-leading-order (NNLO) theoretical predictions, accounting for a range of uncertainties from scale dependence and numerical integration. From the scale choices available for the calculations, our analysis shows that the central predictions for inclusive jet production show a smaller scale dependence than dijet production. We examine the relative constraints on the gluon distribution provided by the inclusive jet and dijet distributions, and also explore the phenomenological implications for inclusive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>H</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mi>H</mi></math> production at the LHC at 14 TeV.</p>

Alim Ablat

Sayipjamal Dulat

Tie-Jiun Hou

Joey Huston

Pavel Nadolsky

Ibrahim Sitiwaldi

Keping Xie

Impact of LHC precision measurements of inclusive jet and dijet production on the CTEQ-TEA global PDF fit

The recent collider detector at fermilab (CDF) <math><mi>W</mi></math> mass measurement of <math><mrow><mn>80</mn><mo>,</mo><mn>433</mn><mo>±</mo><mn>9</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></mrow></math> is the most precise direct measurement. However, this result deviates from the Standard Model predicted mass of <math><mrow><mn>80</mn><mo>,</mo><mn>359.1</mn><mo>±</mo><mn>5.2</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></mrow></math> by <math><mn>7</mn><mi>σ</mi></math>. The CDF experiment used an older version of the resbos code that was only accurate at <math><mrow><mi>NNLL</mi><mo>+</mo><mi>NLO</mi></mrow></math>, while the resbos2 code is able to make predictions at <math><mrow><msup><mrow><mi>N</mi></mrow><mrow><mn>3</mn></mrow></msup><mi>LL</mi><mo>+</mo><mi>NNLO</mi></mrow></math> accuracy. We determine that the data-driven techniques used by CDF capture most of the higher order corrections, and using higher order corrections would have an impact on the CDF result in total at the 10 MeV level. Additionally, we investigate the effects from handling the width of the <math><mi>W</mi></math> boson on the mass, PDF correlations, and scale uncertainties. We find that these contributions are consistent with those obtained by CDF.

Joshua Isaacson

Yao Fu

resbos2 and the CDF <math><mi>W</mi></math> mass measurement

The resummation calculation (resbos) is a widely used tool for the simulation of single vector boson production at colliders. In this work, we develop a significant improvement over the resbos code by increasing the accuracy from <math><mrow><mi>NNLL</mi><mo>+</mo><mi>NLO</mi></mrow></math> to <math><mrow><msup><mrow><mi>N</mi></mrow><mrow><mn>3</mn></mrow></msup><mi>LL</mi><mo>+</mo><mi>NNLO</mi></mrow></math> and release the resbos v2.0 code. Furthermore, we propose a new nonperturbative function that includes information about the rapidity of the system (IFY). The IFY functional form was fitted to data from fixed target experiments, the Tevatron, and the LHC. We find that the nonperturbative function has mild rapidity dependence based on the results of the fit.

Improving resbos for the precision needs of the LHC

Determining the CP property of the Higgs boson is important for a precision test of the Standard Model as well as for the search for new physics. We propose a novel jet substructure observable based on the azimuthal anisotropy in a linearly polarized gluon jet that is produced in association with a Higgs boson at hadron colliders, and demonstrate that it provides a new CP-odd observable for determining the CP property of the Higgs-top interaction. We introduce a factorization formalism to define a polarized gluon jet function with the insertion of an infrared-safe azimuthal observable to capture the linear polarization.

Zhite Yu

Kirtimaan A. Mohan

Determining the Property of Coupling via a Novel jet Substructure Observable

We present a state-of-the-art prediction for cross sections of neutrino deep inelastic scattering (DIS) from nucleon at high neutrino energies, <math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>ν</mi></mrow></msub></mrow></math>, up to 1000 EeV (<math><msup><mn>10</mn><mn>12</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>). Our calculations are based on the latest CT18 NNLO parton distribution functions (PDFs) and their associated uncertainties. To make predictions for the highest energies, we extrapolate the PDFs to small <math><mi>x</mi></math> according to several procedures and assumptions, thus affecting the uncertainties at ultrahigh <math><msub><mi>E</mi><mi>ν</mi></msub></math>; we quantify the uncertainties corresponding to these choices. Similarly, we quantify the uncertainties introduced by the nuclear corrections that are required to evaluate neutrino-nuclear cross sections for the neutrino observatories. These results can be applied to currently running astrophysical neutrino observatories, such as IceCube and KM3NeT, as well as various future experiments that have been proposed.

Jun Gao

T. J. Hobbs

Daniel R. Stump

High-energy neutrino deep inelastic scattering cross sections

The impact of recent LHC top-quark pair production single differential cross section measurements at 13 TeV collision energy on the structure of the proton is explored. In particular, the impact of these high-precision data on the gluon and other parton distribution functions (PDFs) of the proton at intermediate and large partonic momentum fraction <math><mi>x</mi></math> is analyzed. This study extends the CT18 global analysis framework to include these new data. The interplay between top-quark pair and inclusive jet production as well as other processes at the LHC, is studied. In addition, a study of the impact of scale choice on the theory description of the new 13 TeV <math><mi>t</mi><mover><mi>t</mi><mo>¯</mo></mover></math> measurements is performed.

Marco Guzzi

Exploring the impact of high-precision top-quark pair production data on the structure of the proton at the LHC

The forward-backward asymmetry of the Drell-Yan process in dilepton decays at high invariant masses can be used to probe the parton distribution functions at large <math><mi>x</mi></math>. The behavior of three modern parton distribution function sets (CT18NNLO, MSHT20, and NNPDF4.0) are compared, and updated under various scenarios via epump using proton-proton collision pseudodata generated at <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> with <math><mn>3000</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> of integrated luminosity.

Raymond Brock

Daniel Hayden

Probing parton distribution functions at large <math><mrow><mi>x</mi></mrow></math> via Drell-Yan forward-backward asymmetry

The question of the existence and possible magnitude of nonperturbative (often called “intrinsic”) charm in the proton has long confounded attempts to cleanly isolate such a contribution in global analyses of high-energy experiments. In this letter, we show that the available (non)perturbative QCD theory and hadronic data have still not developed to a sufficient level to clearly resolve this problem. We highlight a number of challenging aspects that must be confronted in extracting nonperturbative charm in PDF fits, and in so doing, present an updated next-to-next-to-leading order CT analysis of fitted charm, CT18 FC, which we also compare to recent studies. We outline the theory developments and future data needed to make progress on this subject.

T.J. Hobbs

The persistent nonperturbative charm enigma

Electroweak dipole operators in the standard-model-effective-field theory (SMEFT) are important indirect probes of quantum effects of new physics beyond the standard model (SM), yet they remain poorly constrained by current experimental analyses for lack of interference with the SM amplitudes in constructing cross section observables. In this Letter, we point out that dipole operators flip fermion helicities and so are ideally studied through single transverse spin asymmetries. We illustrate this at a future electron-positron collider with transversely polarized beams, where such an effect exhibits as azimuthal <math><mrow><mi>cos</mi><mi>ϕ</mi></mrow></math> and <math><mi>sin</mi><mi>ϕ</mi></math> distributions which originate from the interference of the electron dipole operators with the SM and are linearly dependent on their Wilson coefficients. This new method can improve the current constraints on the electron dipole couplings by 1–2 orders of magnitude, without depending on other new physics operators, and can also simultaneously constrain both their real and imaginary parts, offering a new opportunity for probing potential <math><mi>C</mi><mi>P</mi></math>-violating effects.