We compute all the $\textit{leading-twist}$ azimuthal spin asymmetries in the pion-proton induced Drell–Yan process. These spin asymmetries arise from convolutions of the leading-twist transverse-momentum-dependent parton distributions (TMDs) of both the incoming pion and the target proton. We employ the holographic light-front pion wave functions for the pion TMDs, while for the proton TMDs, we utilize a light-front quark-spectator model constructed by the soft-wall AdS/QCD. The gluon rescattering is crucial to predict nonzero time-reversal odd TMDs. We study the utility of a nonperturbative SU(3) gluon rescattering kernel, which extends beyond the typical assumption of perturbative U(1) gluons. Subsequently, we employ Collins–Soper scale evolution at Next-to-Leading Logarithmic precision for the TMDs evolution. Our predictions for the spin asymmetries are consistent with the available experimental data from COMPASS and other phenomenological studies. We also present the cross section for the pion-nucleus induced Drell–Yan process with the obtained pion TMDs supplemented by the TMDs of the target nucleus.

India

Bheemsehan Gurjar

China

Chandan Mondal

Azimuthal spin asymmetries in pion-polarized proton induced Drell–Yan process at COMPASS using holographic light-front QCD

We present a fit of the transverse momentum spectrum for Drell-Yan and semi-inclusive deep inelastic scattering data, based on transverse momentum dependent (TMD) factorization at N LL accuracy. Our analysis shows good agreement with the data and confirms the findings of previous studies. Based on this, we extract the unpolarized TMD parton distribution functions, the TMD fragmentation functions, and the Collins-Soper kernel. Compared to earlier works, our study incorporates several improvements, including large-$\textit{x}$ resummation, flavor and fragmentation function dependence, among others. Additionally, we supplement our extraction with an analysis of the transverse momentum moments of the extracted distributions.

Taiwan

Valentin Moos

Spain

Ignazio Scimemi

Alexey Vladimirov

Pia Zurita

Determination of unpolarized TMD distributions from the fit of Drell-Yan and SIDIS data at N

We present partonic contributions to the inclusive gluon-fusion Higgs boson and Drell-Yan production cross sections at Hadron colliders at next-to-next-to-next-to-next-to-leading order (N LO). Specifically, we compute contributions due to the interference of one-loop amplitudes with two-loop amplitudes with three QCD partons and the Higgs boson or a virtual photon. Our result is in the form of a Laurent expansion in the dimensional regulator $\textit{ϵ}$, the coefficients of which are analytic functions in the ratio of the Higgs boson or virtual photon mass to the partonic center-of-mass energy. Furthermore, we introduce and deploy a new package implemented in Mathematica, Cifar (“Color Invariant Feynman Amplitude Reducer”), to express color factors in terms of general Casimir invariants of simple compact Lie algebras.

United States

Bernhard Mistlberger

Adi Suresh

RVV×V: interference contributions to inclusive Higgs boson and Drell-Yan production at N

We investigate nuclear modification and the universality of short-range correlation (SRC) in pion-induced Drell–Yan process. Employing nuclear parton distribution functions (nPDFs) and pion PDFs, the ratio of differential cross sections of different nuclei relative to the free nucleon is presented. A kind of universal modification function was proposed which would provide nontrivial tests of SRC universality on the platform of pion-induced Drell–Yan. This work improves our understanding of nuclear structure and strong interactions.

Fei Huang

Shu-Man Hu

De-Min Li

Ji Xu

Test for universality of short-range correlations in pion-induced Drell–Yan process

We reinterpret the Nieh-Yan (NY) anomaly using holography, finding that the U(1) axial symmetry remains unbroken and the axial current coupling to an external gauge field is conserved. Instead, the anomaly arises from a breakdown of Hodge duality relations between fermion bilinears due to symmetry constraints on one-form currents. We show that the axial response associated with the NY term is distinct from the chiral vortical effect and exhibits a characteristic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>T</mi><mn>2</mn></msup></math> dependence. Torsion-induced axial transport decouples spin and axial charge dynamics, thereby clarifying the physical significance of the NY anomaly and motivating further field-theoretic and holographic studies.

Carlos Hoyos

Finland

Niko Jokela

Italy

José Manuel Penín

Thermal response of the Nieh-Yan term

We present a comprehensive analysis of the angular structure of the Drell-Yan process at different rapidity and kinematical ranges using predictions of theoretical approaches (collinear perturbative QCD and the geometrical method) at next-to-leading order and data of ATLAS, LHCb, and CMS Collaborations at the CERN LHC.

Chile

Germany

Valery E. Lyubovitskij

JINR

Russia

Alexey S. Zhevlakov

Iurii Anikin

Angular coefficients of the Drell-Yan process across different rapidity and kinematical ranges

We propose a two-dimensional superstring sigma model that defines a self-contained corner of heterotic string theory, whose second quantization is heterotic matrix string theory. This worldsheet theory arises from a BPS decoupling limit that zooms in on the heterotic string, under which the target space geometry becomes non-Lorentzian. This construction generalizes the Gomis-Ooguri formulation of non-relativistic string theory to the heterotic case. We show how such a worldsheet theory provides a first-principles definition of the heterotic string in the discrete light cone quantization via T-duality. By turning on a current-current deformation akin to a $$ T\overline{T} $$ deformation, the conventional heterotic string theory with a Lorentzian target space is recovered. We analyze the gauge and gravitational anomalies with respect to the lowest-order quantum corrections in the sigma model and show how the worldsheet theory is consistent with non-Lorentzian supergravity in the target space.

Netherlands

Eric Bergshoeff

Philippines

Kevin Grosvenor

Luca Romano

Sweden

Ziqi Yan

Heterotic string sigma models: discrete light cone quantization and its current-current deformation

We present results for the Drell-Yan process $\textit{pp}$ → $\textit{Z}$/$\textit{γ}$ + $\textit{X}$ → $\textit{l}$ $\textit{l}$ + $\textit{X}$ in the presence of the rapidity dependent jet vetoes $$ {\mathcal{T}}_{Bj} $$ and $$ {\mathcal{T}}_{Cj} $$ . These observables provide a tighter veto at central rapidities than at forward rapidities. Our predictions contain a resummation of large logarithms of the veto scale over the hard scale, matched to fixed order in perturbation theory; we present results at both NLL +NLO and NNLL +NNLO. Uncertainty estimates are provided that contain both resummation and fixed-order uncertainties; we find that using a standard profile scale variation procedure for the former seems to underestimate the uncertainty, particularly at NLL +NLO. Consequently, we modify the procedure to avoid cancellation of scale variations between partonic channels, and verify that the uncertainties from this method are reasonable using a simplified version of the Theory Nuisance Parameter (TNP) method. We then find that the uncertainty decreases going from the NLL +NLO to the NNLL +NNLO predictions, and obtain an uncertainty at the level of 1 − 3% in the NNLL +NNLO predictions when the veto scale is of 𝒪(10 GeV).

United Kingdom

Thomas Clark

Shireen Gangal

Jonathan Gaunt

The Drell-Yan process at NNLL

We study $ \cos2\phi $ azimuthal asymmetry in doubly longitudinally polarized proton-proton Drell-Yan collisions within the transverse momentum dependent factorization framework. The asymmetry arises from the convolution of the longitudinal transversity distribution $ h_{1L}^{\perp} $ for both protons. Using the Bacchetta-Delcarro-Pisano-Radici-Signori parameterization for the nonperturbative Sudakov form factor and the Wandzura-Wilczek approximation for collinear $ h_{1L}^{\perp} $ , we predict the double spin asymmetry $ A_{LL}^{\cos2\phi} $ at RHIC and NICA kinematics. Our results demonstrate sensitivity to sea quark distributions, with the asymmetry reaching up to 25% for maximal sea quark contributions. These predictions highlight the potential of polarized Drell-Yan measurements to probe sea quark dynamics and advance our understanding of nucleon structures.

Hui Li

Ting Hu

Liang-Liang Liu

Xiao-Yu Wang

Zhun Lu

Asymmetry ${{\boldsymbol A}_{\boldsymbol{LL}}^{\bf\cos2\boldsymbol\phi}} $ in the polarized proton-proton Drell-Yan process within TMD factorization * Hui Li is supported by Fundamental Research Program of Shanxi Province (202203021222224) and Natural Science Foundation of Shanxi Normal University (JCYJ2023021). Xiao-Yu Wang is supported by the Natural Science Foundation of Henan Province (242300421377, 232300421140)

We study Drell-Yan production in universal theories consistently including effects beyond dimension six in the Standard Model effective field theory (SMEFT). Within universal SMEFT and with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math> conservation we find that 11 dimension-eight operators contribute in addition to the six contributing at dimension six. We first work in an operator basis in which operators with higher derivatives of the bosonic fields have been rotated by equations of motion in favor of combinations of operators involving SM fermion currents. We derive the general form of the amplitudes consistently in the expansion to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mi mathvariant="normal">Λ</mi><mrow><mo>−</mo><mn>4</mn></mrow></msup><mo stretchy="false">)</mo></math> and identify eight combinations of the 17 Wilson coefficients which are physically distinguishable by studying the invariant mass distribution of the lepton pairs produced. We then introduce an extension of the parametrization of universal effects in terms of oblique parameters obtained by linearly expanding the self-energies of the electroweak gauge bosons to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mi>q</mi><mn>6</mn></msup><mo stretchy="false">)</mo></math>. It contains 11 oblique parameters of which only eight are generated within SMEFT at dimension eight: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>S</mi><mo stretchy="false">^</mo></mover></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>T</mi><mo stretchy="false">^</mo></mover></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>U</mi><mo stretchy="false">^</mo></mover></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math>, plus two additional which we label <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Y</mi><mo>′</mo></msup></math> and show how they match at linear order with the eight identified combinations of operator coefficients. We then perform a combined analysis of a variety of LHC data on the neutral- and charged-current Drell-Yan processes with the aim of constraining the eight combinations. We compare and combine the LHC bounds with those from electroweak precision <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> pole observables which can only provide constraints in four directions of the eight-parameter space. We present the results in terms of limits on the eight effective Wilson coefficients as well as on the eight oblique parameters. In each case, we study the dependence of the derived constraints on the order of the expansion considered.