We study one-loop QCD corrections to the single transverse spin asymmetry in Drell-Yan process. The invariant mass of virtual photon and angular distributions of final lepton in Collins-Soper frame are measured. Especially, the transverse momentum of virtual photon is integrated out. Collinear twist-3 factorization formalism is adopted for the asymmetry. We use Feynman gauge in this work. To eliminate dependent twist-3 distribution functions, equation of motion for quark is used. The results satisfy both QED and QCD gauge invariance. It is confirmed that all divergences from virtual and real corrections can be removed consistently by collinear subtraction. Finite hard coefficients for the convolution of $$ \overline{q}(x) $$ and $\textit{T}$ ($\textit{x}$ , $\textit{x}$ ) are presented.

China

Guang-Peng Zhang

One-loop QCD corrections to SSA in unweighted Drell-Yan processes

We present a thorough investigation of the sources of uncertainties to the Drell-Yan production using state-of-the-art predictions for both neutral and charged current channels, focusing on the low invariant mass region. Differential predictions for the invariant mass spectrum are provided at N LO supplemented with exact charm and bottom quark mass effects calculated at $$ \mathcal{O}\left({\alpha}_s^2\right) $$ . The impact of PDF choices (including approximate N LO), scale variations, the variation of the strong coupling constant, and impact heavy quark mass effects on the distributions is studied in detail. We also comment on the correlation of high-energy astrophysical processes with the low-mass DY region.

Germany

Ekta Chaubey

Claude Duhr

Rhorry Gauld

Pooja Mukherjee

A comprehensive analysis of Drell-Yan production uncertainties and mass effects at moderate and low dilepton masses

In this paper, we present three types of teleparallel frames with cylindrical and spherical symmetry. The first example is the closed time-like curves (CTC) in cosmic strings in teleparallel $$T_{4}$$ gravity, which shows they are forbidden. Here, we show that in $$T_{4}$$ , in order to allow for CTC, we are also led to a lower bound on the angular momentum of the cosmic string. This result matches the interior $$T_{4}$$ solution to a General Relativity (GR) vacuum solution. One of the main differences between the present report and the one by Soleng is that, here, the interior symmetric solution does not have polarized spins but only Cartan torsion in the spirit of teleparallelism. Torsion flux is computed to show that a cylindrical central singularity corresponds to a $$(2+1)$$ -spacetime rotating point particle in $$T_{4}$$ . Therefore, the possibility of building time machines seems to be strongly constrained compared with Einstein–Cartan (EC) gravity. We present a spherically symmetric black hole with an open string along a particular direction of the black hole (BH). In this case, it is shown that when the teleparallel frame used is the one where all spin coefficients vanish, a torsion flux cutoff appears along one of the directions. In the stringy BH case, choosing a restricted teleparallel frame, a torsion-axion-like hair appears in the form of an axion scalar. A Kerr Nieh–Yan (NY) invariant black hole is obtained. Coley et al. previously obtained BH solutions in teleparallel spacetime, which present horizon singularities but not torsion singularities.

Brazil

Croatia

L. Garcia de Andrade

Strings in Gödel CTC and in hairy axionic black holes with Kerr Nieh–Yan charges in teleparallelism

We present results from a global fit of Standard Model parameters and dimension-6 SMEFT Wilson coefficients that includes electroweak, Drell-Yan, Higgs-boson, top-quark, and flavour observables. Fits obtained by floating individual coefficients are also discussed. The leading-order scale dependence of the SMEFT Wilson coefficients is consistently included in the evolution from the UV scale to the electroweak scale and the low-energy scale of flavour observables. In defining the SMEFT set of active operators we consider both the U(3) and the U(2) flavour symmetric limits. All fits are obtained within the HEPfit framework and are based on the most recent experimental results and state-of-the-art theoretical predictions for all the observables considered.

Spain

Jorge Blas

United States

Angelica Goncalves

United Kingdom

Víctor Miralles

Laura Reina

Italy

Luca Silvestrini

Mauro Valli

Constraining new physics effective interactions via a global fit of electroweak, Drell-Yan, Higgs, top, and flavour observables

We consider the transverse-momentum ($\textit{q}$ ) distribution of Drell-Yan lepton pairs produced with invariant masses ($\textit{M}$) from low values up to the $\textit{Z}$-boson peak (4 $\textit{≤ M ≤}$ 116 GeV). We present perturbative predictions obtained by consistently combining the resummation of logarithmically enhanced QCD corrections at small $\textit{q}$ ($\textit{q}$ ≪ $\textit{M}$) up to next-to-next-to-next-to-next-to-leading logarithmic accuracy with the available fixed-order calculations at next-to-next-to-leading order (i.e. $$\mathcal{O}({\alpha }_{S}^{3})$$ ) valid at large $\textit{q}$ . For very low $\textit{q}$ ($\textit{q}$ ~ Λ ), non-perturbative (NP) QCD effects become dominant and have been included through a NP form factor with a small number of free-parameters. We compare our results with multiple experimental datasets from hadron colliders, finding excellent agreement between theory and data. By fitting the NP parameters, we achieve a precise extraction of the NP form factor and the so-called Collins-Soper kernel.

Switzerland

Stefano Camarda

Giancarlo Ferrera

Lorenzo Rossi

Drell-Yan lepton pair production at low invariant masses: transverse-momentum resummation and non-perturbative effects in QCD

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

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

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.

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

<p>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.</p>