RADCOR 2025 – 17th International Symposium on Radiative Corrections: Applications of Quantum Field Theory to Phenomenology

5 Oct 2025, 16:00 → 10 Oct 2025, 17:30 Asia/Kolkata

Kalinga Hall (Empires Hotel)

Narayan Rana (National Institute of Science Education and Research (NISER) (IN))

This conference is the 17^th in the series of biennial RADCOR conferences on radiative corrections. It is devoted to the applications of quantum field theory to particle physics phenomenology. Subjects will include precision calculations for colliders, progress in higher-loop and higher-multiplicity calculations in the Standard Model, cross-sections for new physics, interpretations of experimental data, new techniques for calculations, advances in computer-algebra methods, new theoretical developments.

The conference will be held in Puri, a historic coastal city in eastern India. The venue is the Empires Hotel, Puri, which offers half-board packages for conference participants, as detailed on the Accommodation page.

For VISA requirements, a two-step registration procedure will be followed. Anyone interested in participating should pre-register now on the Indico page and submit a copy of the front page of their passport, along with the completed Annex-II form, to radcor25 [AT] niser.ac.in. Pre-registration details are essential for obtaining the DAE approval and a clearance letter from the MEA, India, which is required to apply for a conference VISA. Once we receive your pre-registration details, we will proceed to obtain both the documents, and will notify you upon receipt. For further details, please refer to the visa information page. 

Upon receipt of both documents from us, you may proceed with your visa application. Upon obtaining a visa, you can complete the final registration process, which includes paying the registration fee, submitting talk details, and providing information regarding hotel booking. By completing the final registration process, participants confirm their commitment. 

 

The conference will be held exclusively in offline mode.

 

Organizing Committee    
S. Basak (NISER)    
N. Haque (NISER)    
M. C. Kumar (IIT G)    
N. Rana (NISER) - Chair    
V. Ravindran (IMSc)
S. Seth (PRL)    
A. Shivaji (IISER M)    
A. Tripathi (IIT H)

International Advisory Board     
M. Beneke (TU Munich)    
Z. Bern (UCLA)    
S. J. Brodsky (SLAC)    
M. Cacciari (LPTHE, Jussieu)    
C. Duhr (Bonn) - Vice Chair    
R. K. Ellis (IPPP, Durham)    
F. Febres Cordero (FSU)    
J. Fujimoto (KEK)    
E. Gardi (Edinburgh)    
A. Hoang (Vienna) - Chair    
W. Hollik (MPI Munich)    
M. Kobayashi (KEK)    
D. Kosower (IPhT, CEA-Saclay)    
P. Marquard (DESY)    
P. Mathews (SINP)    
V. Ravindran (IMSc)    
L. Reina (FSU)    
C. Schneider (RISC, JKU Linz)    
J. Sola (Barcelona)    
M. Steinhauser (KIT)    
H. Sugawara (OIST)    
B. F. L. Ward (Baylor)    
H. X. Zhu (Peking)

radcor25.png

Sunday 5 October

16:30 → 19:00 Conference Registration

19:00 → 20:00 Inaugural gathering

20:00 → 22:00 Dinner

Monday 6 October

09:00 → 11:00 Kalinga

09:00 Inauguration

09:30 Recent results from ALICE

Speaker: Bedangadas Mohanty (National Institute of Science Education and Research (NISER) (IN))

RADCOR-Puri-Bedanga-final-Oct2025.pdf

10:00 CMS physics results and upgrades

Speakers: Sanjay Kumar Swain (National Institute of Science Education and Research (NISER) (IN)), Sanjay Swain

RADCOR-SANJAY.pdf

10:30 Recent results from CMS: Higgs

Speaker: Rajdeep Mohan Chatterjee (Tata Institute of Fundamental Research (IN))

RADCOR25_CMS_Higgs_RMC.pdf

11:00 → 11:30 Tea break

11:30 → 13:00 Kalinga

11:30 Factorization and Resummation of LHC Jet Processes

We analyze the low-energy dynamics of jets cross sections at hadron colliders, for which phase factors in the hard amplitudes spoil collinear cancellations and lead to double (“super-leading”) logarithmic behavior. Based on a method-of-regions analysis, we identify three-loop contributions from perturbative Glauber-gluon exchanges with the right structure to render the cross section consistent with PDF factorization below the gap veto scale. The Glauber contributions we identify are unambiguously defined without regulators beyond dimensional regularization.

Speaker: Matthias Neubert

Neubert_RADCOR_Oct2025.pdf

12:00 Towards NNLO QCD predictions for off-shell top-quark pair production and decays

We consider QCD radiative corrections to WWbb production with leptonic decays and massive bottom quarks at the LHC. Non-resonant and off-shell effects related to the top quarks and the leptonic decays of the W± bosons are consistently included. We evaluate the double-virtual contribution in the double-pole approximation. We present first results for the inclusive cross section in NNLO QCD.

Speaker: Massimiliano Grazzini (University of Zurich (CH))

Grazzini_Radcor_2025.pdf

12:30 Progress on the soft anomalous dimension in QCD

Recently we completed another step in determining the soft anomalous dimension in QCD, accounting for interactions between a single massive coloured particle and any number of massless ones at three loops. This was achieved using a new approach to the problem based on the method of regions. In this talk I review the state of the art knowldge of long-distance singularities, present the new ideas facilitating the recent progress and discuss the properties of the final result.

Speaker: Einan Gardi

RADCOR_Oct_2025_Gardi.key.pdf

13:00 → 14:30 Lunch

14:30 → 16:00 Coral 1

14:30 Locally finite two-loop amplitudes for photoproduction in quark annihilation

Precise predictions for increasingly complex processes at higher perturbative orders call for a process-independent algorithm that can numerically integrate multi-loop amplitudes directly in momentum space. However, Feynman amplitudes are plagued by infrared and ultraviolet singularities which must be removed at the integrand level before numerical integration can be performed. In recent years, substantial progress has been made toward a framework that constructs locally finite two-loop amplitudes for a broad class of processes by making the factorization of infrared singularities manifest at the integrand level. In a previous work, two-loop QCD amplitudes for colorless, off-shell production processes initiated by quark-antiquark annihilation was rendered locally finite. In this work, we present an extension of this approach to processes involving real photons in the final state. Such final states introduce new transient singularities that vanish upon integration but still require local subtraction. We outline the methods developed to remove these singularities, preparing the amplitude for numerical integration. This work is a significant step toward applying factorization-based IR subtraction methods to a wider range of processes, particularly those involving final-state jets.

Speaker: Roshni Sahoo (ETH Zurich (CH))

radcor_2025_roshni_sahoo.pdf

15:00 Numerical integration of colorless final-state production via quark-antiquark annihilation at two-loops: the fermion loop contributions and beyond

We present recent advances in the numerical integration of two-loop scattering amplitudes for the production of 2 and 3 vector bosons via quark-antiquark annihilation. The numerical integration is performed directly in loop momentum space. This is made possible by the simultaneous local subtraction of infrared, ultraviolet, and threshold singularities (more details are given in Dario Kermanschah's contribution). In this talk, I will focus on the recent computation of the fermion loop contributions and share ongoing progress toward obtaining fully numerical results for the complete two-loop amplitude for di-photon production.

Speaker: Matilde Vicini

RADCOR_2025_matilde_vicini_final.pdf

15:30 Numerical integration of two-loop corrections to electroweak production at the LHC

In this talk, I will present a numerical method developed for computing double virtual contributions to electroweak vector boson production. Our approach performs a local subtraction of infrared and ultraviolet singularities, implementing factorisation and renormalisation locally in momentum space. We then analytically integrate the energy components of the loop momenta and locally subtract threshold singularities. The resulting finite remainder is integrated numerically using Monte Carlo methods. I will provide an overview of the method, its implementation and discuss selected results. Details of our recent calculation of the fermion-loop contributions for up to three massive final-state bosons, as well as first steps towards the full two-loop correction to diphoton production are discussed in the presentation by Matilde Vicini.

Speaker: Dario Kermanschah

radcor25_dario.pdf

14:30 → 16:00 Coral 2

14:30 $t\bar{t}H$ production at NLO using perturbative fragmentation functions

The production of a Higgs boson in association with a top-antitop pair at hadron colliders can be described via a factorisation formula using perturbative fragmentation functions. The fragmentation functions describe the collinear splitting of a top-quark or gluon to a Higgs boson and reproduce the leading mass dependence of the exact NLO calculation. Although the formalism has been understood for quite some time, and the NLO fragmentation functions have been calculated a few years ago, it has not been possible up to now to demonstrate the applicability of the approximation in a realistic setup. At NLO, I will show that the method works with massive top quarks for the case of the LHC, but the massless top-quark limit is only reliable at a 100 TeV hadron collider.

Speaker: Benedikt Gurdon

RADCOR25_Gurdon.pdf

15:00 One-loop Amplitudes for $t \bar{t} j$ and $t \bar{t} \gamma$ Productions at the LHC

We present analytic expressions for the one-loop QCD helicity amplitudes contributing to top-quark pair production in association with a photon or a jet at the Large Hadron Collider (LHC), evaluated through $O(\epsilon^2)$ in the dimensional regularisation parameter, $\epsilon$. These amplitudes are required to construct the two-loop hard functions that enter the NNLO QCD computation. The helicity amplitudes are expressed as linear combinations of algebraically independent components of the $\epsilon$-expanded master integrals, with the corresponding rational coefficients written in terms of momentum-twistor variables. We derive differential equations for the pentagon functions, which enable efficient numerical evaluation via generalised power series expansion method.

Speaker: Souvik Bera

RADCOR25_SB_tta.pdf

15:30 One-Loop QCD Corrections to $\bar{u}d \rightarrow t\bar{t}W$ at $\mathcal{O}(\varepsilon^2)$

Physical observables described by 2 → 3 scattering amplitudes have been a focal point of intense research in recent years. In particular, amplitudes with massive internal propagators are phenomenologically relevant as they represent the bottleneck of obtaining next-to-next-to-leading order (NNLO) QCD corrections to a variety of different processes, and at the same time pose interesting computational challenges. Among these processes, the associated production of a top-antitop pair with a W boson (ttW) is of particular interest. Not only is it relevant to searches for physics beyond the Standard Model, but it also serves as a significant background for important Standard Model processes. As a first step towards an exact description of this process at NNLO in QCD, I present our analytic computation of the one-loop QCD corrections to this process up to finite order in dimensional regularization and a semi-numerical computation of the terms at higher orders. I will emphasise both open conceptual problems and technical challenges, highlighting a possible way forward to extend these results to the two-loop order.

Speaker: Sara Ditsch

Talk-Ditsch.pdf

16:00 → 16:30 Tea Break

16:30 → 18:00 Coral 1

16:30 Integration techniques for worldline integrals

The worldline formalism allows one to obtain compact integral representations combining the information of large numbers of Feynman diagrams. However, their analytic calculation leads to a non-standard integration problem for which existing mathematical algorithms are of little help. Here I will summarize the state-of-the-art of worldline integration focusing on examples from QED in vacuum and in constant external fields.

Speaker: Christian Schubert (Universidad Michoacana de San Nicolas de Hidalgo)

talk_radcor25.pdf

17:00 Higher order predictions for Hadronic Higgs decay

The prospect of future electron-positron colliders operating as "Higgs factories" in a clean experimental environment presents one of the most promising avenues for Higgs precision measurements. In order to capitalise on this, we need to have good theoretical control over these obvservables. In this talk, I will report on recent calculations in Hadronic Higgs decays, focusing in particular on the variations between the dominant H->b \bar{b} channel via a Yukawa interaction, and the sub-dominant H->gg channel. Using the newly-developed "generalised antenna formalism", we have been able to caluclate jet-rates and classical QCD event-shape observables up to NNLO accuracy, providing us with the means to quantify the differences between the two decay modes.

Speaker: Elliot Fox (Durham University)

RADCOR25.pdf

17:30 High-precision black hole scattering at four-loop order

This talk will discuss the calculation of the impulse of a classical black hole scattering event at fifth Post-Minkowskian order. This calculation will contribute to new high precision waveform templates, which are needed for the new generation of gravitational wave detectors. I will describe the "worldline quantum field theory” formalism and the state of the art integration techniques that are needed to do this computation. In particular I will discuss advanced integration-by-part relations and the emergence of Calabi-Yau periods and how to deal with them using the technique of differential equations. These techniques will also be relevant for future particle physics computations.

Speaker: Benjamin Sauer (Humboldt Universitaet zu Berlin)

Radcor.pdf

16:30 → 18:00 Coral 2

16:30 Field theory expansion of string amplitudes

Speaker: Arnab Priya Saha

String_amp_CSDR.pdf

17:00 Small-spin singularities in anomalous dimensions of twist-two operators

Anomalous dimensions of leading-twist operators in QCD play an important role in precision predictions in high-energy processes, since they govern the scale evolution of parton distributions. Their analytic structure as a function of spin is particularly important due to the complexity of higher-loop computations. In the talk, I will discuss the resummation of the right-most singularities of anomalous dimensions in certain theories, with a main focus on the Gross–Neveu–Yukawa model in the epsilon and 1/N expansions, since these singularities share common features with those appearing in the quark flavor-nonsinglet sector of QCD. Such resummation allows one to predict the higher-loop singular behavior and reveals connections with the conformal Regge theory and recent studies of detector operators in QCD and various CFTs. The talk is based on arXiv:[2506.05132].

Speaker: Leonid Shumilov

radcor25_shumilov.pdf

17:30 The Landau Bootstrap

Although physical principles such as causality and locality are believed to have far-reaching implications for loop-level scattering amplitudes, the concrete form of these constraints has remained hard to work out in practice. In this talk, I will give an overview of recent progress towards working out these constraints for individual Feynman integrals. I will also describe how these constraints can be fed into a bootstrap approach, via which the functional form of Feynman integrals can be determined from just knowledge of their singular behavior.

Speaker: Andrew Jordan Mcleod (The University of Edinburgh (GB))

The Landau Boostrap.pdf

20:00 → 22:00 Dinner

Tuesday 7 October

09:00 → 11:00 Coral 1

09:00 Mixed QCD-EW corrections to the Drell-Yan process

In this talk, I report on the complete computation of the mixed QCD–electroweak corrections to the neutral-current Drell–Yan process. I present phenomenological results for several kinematical distributions including the forward–backward asymmetry, which is a key observable to measure the weak mixing angle. Special focus will be devoted to the theoretical challenges of the computation, with particular attention to the evaluation of the two-loop amplitudes.

Speaker: Simone Devoto (Universiteit Gent)

Radcor25.pdf

09:30 Two-loop planar master integrals for charged current Drell-Yan production of massless electron-positron pair through bottom-antibottom channel

We present analytic expressions for the two-loop planar master integrals for charged current Drell-Yan production of massless electron-positron pair through bottom-antibottom annihilation channel. We find two additional planar topologies over the topologies in the four-flavor scheme where the top quark is present as an internal line, i.e., double-box and penta-triangle topologies. The double-box topology has 46 master integrals, while the penta-triangle one has 44 master integrals. We use the method of differential equations to obtain analytical expression of the master integrals.

Speaker: Debashis Saha

Drell-Yan_DS.pdf

10:00 Three loop master integrals for O(ααs2) corrections to quark form factor

The standard model (SM) is one of the most successful theories which can accurately describe the behavior of fundamental particles and their interactions. Many SM inputs, in fact, the number of particles and their mass, etc, are driven out of the experiment, and many fundamental questions arise on this structure. As experiments achieve more and more precision, we are supposed to get a high-resolution picture of the SM. We need theoretical advancements parallel to the experimental accuracy to understand the underlying structure or unambiguously validate the beyond SM phenomena if they exist. In this talk, I will present some of our results towards calculating the total cross-section for on-shell $Z$ boson production at the hadron collider, a standard candle from both theoretical and experimental points of view. We will briefly summarize the calculation of master integral and vector form factors.

Speaker: Tanmoy Pati

radcor2025_Tanmoy.pdf

10:30 Four-loop QCD corrections to the massless axial vector form factor

We present the computation of the four-loop QCD corrections to the massless quark form factor with an external axial-vector current. Particular attention is devoted to the singlet contributions, which require a careful and consistent treatment of the axial current and γ₅ within dimensional regularisation. We analyze the ultraviolet renormalization and elucidate the infrared pole structure of the form factor in this order. Our results provide virtual ingredients for future precision studies of Z boson production at N^4LO QCD.

Speaker: Amlan Chakraborty (The Institute Of Mathematical Sceinces)

Radcor-amlan-2025.pdf

09:00 → 11:00 Coral 2

09:00 Invariant-Mass Threshold Resummation for Four Top- Quark Production at the LHC

The production of four top quarks is one of the rarest processes in the Standard Model, and it was finally observed in 2023 at the LHC. Studying this process offers valuable insights into the top-Higgs interaction and may reveal new physics. Thus, comparing theoretical predictions with current and future measurements is a crucial test for the Standard Model. In this talk, I will present the most accurate QCD predictions to date for four top-quark production, obtained using invariant-mass threshold resummation at NLL' accuracy, matched to NLO. I will discuss results for both the total cross section and the invariant-mass distribution, highlighting their significance and the improvements made.

Speaker: Michele Lupattelli (Muenster University)

Lupattelli_RADCOR_7Oct_2025.pdf

09:30 Threshold Resummation of Drell-Yan type colorless processes at LHC

We look at the threshold effects in neutral and charged Drell-Yan production, Higgs boson production with a massive vector boson, and Higgs production in bottom quark annihilation at the Large Hadron Collider (LHC), up to the third order in QCD. Using third-order soft-virtual (SV) results and the universal properties of threshold logarithms, we find the process-dependent coefficients and improve the accuracy by including large threshold logarithms up to next-to-next-to-next-to-leading logarithmic (N3LL) order and matched with the latest N3LO results. Additionally, we extend our analysis to the next-to-soft-virtual (NSV) correction for VH processes. We also show numerical results for the invariant mass distributions and total production cross sections for these processes. Our findings show that the theoretical scale uncertainties, which are about 0.4% at N3LO in fixed-order calculations, decrease to less than 0.1% at N3LO+N3LL after SV threshold resummation in the high invariant mass region.

Speaker: Chinmoy Dey

presentation.pdf

10:00 Threshold improved ZH production at the LHC

We present precise results for the $ZH$ production cross section and invariant mass distribution at the LHC taking into account the effects of the leading and sub-leading soft gluons. We improve both quark-initiated and gluon-initiated subprocesses through threshold resummation within the QCD framework.

Speaker: Kajal Samanta (IPPP Durham)

RADCOR2025_kajal.pdf

10:30 VV resummation to NNLO+NNLL at LHC

We study the production of massive vector boson pairs (ZZ and WW) in hadronic collisions, focusing on the threshold region where soft-gluon effects become significant. To improve theoretical predictions in this regime, we perform threshold resummation at next-to-next-to-leading logarithmic (NNLL) accuracy and combine the results with fixed-order NNLO QCD calculations from the public code MATRIX. Our predictions for the invariant mass distributions are thus obtained at NNLO+NNLL accuracy. At current LHC energies, we find that the inclusion of NNLL resummation leads to a modest enhancement of the cross section, particularly in the high invariant mass region. Moreover, resummation substantially reduces theoretical uncertainties associated with variations of the renormalization and factorization scales. Specifically, at an invariant mass of Q = 1.3 TeV, the scale uncertainties decrease from 4.6% to 3.2% for ZZ production and from 4.2% to 3.0% for WW production

Speaker: Vaibhav Pandey

RADCOR25_VAIBHAV_PANDEY.pdf

11:00 → 11:30 Tea Break

11:30 → 13:00 Coral 1

11:30 Fermionic contributions to the 2-loop EW renormalization of the Neutral Current Drell-Yan process

In the following years, the improvement of the high-energy measurements in particle accelerators will permit to obtain levels of accuracy never experienced before. In this scenario, the Drell-Yan process constitutes one of the main LHC processes that will benefit from the increase of the experimental dataset, with a future estimated precision of the order of 0,1% in the 1 TeV invariant mass region. Consequently, in order to perform a statistically significant comparison between theoretical predictions and experimental measurements, the inclusion of NNLO EW corrections in the cross section is required, whose evaluation represents the frontier from the computational point of view. In this talk, I will present our results for the evaluation of the virtual NNLO contributions to the Neutral Current Drell-Yan process, considering at this stage only the Feynman diagrams featuring an internal closed fermion loop. In particular, I will focus on the main aspects of our 2-loop EW renormalization program and the implementation of an automated procedure for the computation of the diagrams featuring first and second order counterterms.

Speaker: Michele Dradi (Università degli Studi di Milano)

Radcor2025_MicheleDradi.pdf

12:00 2-loop QED corrections to the Drell-Yan amplitude and prospects towards full EW results

Speaker: Tommaso Armadillo

radcor2025_armadillo.pdf

11:30 → 13:00 Coral 2

11:30 Decay of pseudoscalar Higgs boson to three partons at higher orders in the dimensional regulator

We present a calculation of the second-order corrections for the decay of a pseudoscalar Higgs boson into three partons, considering higher orders in the dimensional regulator. With the application of suitable crossings, these amplitudes are essential for a complete three-loop cross-section study.

Speaker: Pulak Banerjee (IIT Guwahati)

Pulak_Banerjee_Radcor_2025.pdf

12:00 Towards Three-loop virtual QCD corrections to gg->HH at leading power in the high-energy limit

In this talk, we report progress toward understanding quark mass effects in the $g g \rightarrow HH$ amplitude at NNLO to leading power in the high-energy limit, $s,|t|,|u| \gg m_t^2 \gg m_H^2$. The logarithmic behavior of this process in this regime has recently been shown to exhibit a predictable, factorized pattern at leading power. We present our results for the three-loop virtual QCD corrections in this limit. This result, together with the systematic inclusion of top-quark mass dependence through the running of the coupling and massification procedure, will allow us to capture the dominant logarithmic contributions in the top-quark mass expansion at very high energies. These developments help to improve the theoretical prediction for $g g \rightarrow HH$ at NNLO and have the potential to reduce the associated mass scheme uncertainty, when combined with the real-real and real-virtual contributions.

Speaker: Ajjath Abdul Hameed

diHiggs_Radcor25.pdf

12:30 Towards HH at NNLO QCD: virtual corrections with two top- quark loops

The virtual corrections for gg->HH at NLO QCD have been efficiently approximated using a Taylor expansion in the limit of a forward kinematics. The same method has been recently applied to the calculation of a subset of the NNLO corrections, which are desirable given the significant impact, at NLO, of the uncertainty due to the choice of the top-mass renormalization scheme. In this talk, I will report on the progress in the calculation of another contribution at NNLO, given by diagrams in which the two Higgs bosons couple separately to different top-quark loops. For this contribution a naive Taylor expansion cannot be used, and I will instead discuss an approach based on asymptotic expansions in different kinematic limits.

Speaker: Marco Vitti

Vitti_RADCOR_25.pdf

13:00 → 14:30 Lunch

14:30 → 16:00 Coral 1

14:30 NNLO QCD Corrections to Neutral and Charged Current Semi-Inclusive Deep-Inelastic Scattering

The production of identified hadrons in lepton-nucleon scattering (semi-inclusive deep inelastic scattering, SIDIS) allows for detailed analyses of parton distributions and fragmentation functions. We present our novel calculation of the full set of next-to-next-to leading order (NNLO) QCD corrections to neutral and charged current SIDIS coefficient functions. We study the numerical impact of our results with a focus on the kinematical settings of the future Electron-Ion Collider (EIC). We further highlight the impact that our results will have on the extraction of fragmentation functions from neutrino-induced SIDIS data. Our results enable for the first time a consistent treatment of charged and neutral current induced hadron fragmentation processes in DIS at NNLO in QCD.

Speaker: Leonardo Bonino (Universität Zürich)

Bonino_RADCOR.pdf

15:00 NNLO QCD corrections to unpolarized and polarized SIDIS

The semi-inclusive deep-inelastic scattering (SIDIS) process requires the presence of an identified hadron H′ in the final state, which arises from the scattering of a lepton with an initial hadron P. By employing factorization in quantum chromodynamics (QCD), SIDIS provides essential knowledge on the hadron structure, enabling the exploration of parton distribution functions (PDFs) and fragmentation functions (FFs). The coefficient functions for SIDIS can be calculated in perturbative QCD and are currently known to the next-to-next-to-leading order (NNLO) for the cases, where the incoming lepton and the hadron P are either both polarized or unpolarized. We present a detailed description of these NNLO computations, including a thorough discussion of all the partonic channels, the calculation of the amplitudes and master integrals for the phase-space integration as well as the renormalization of ultraviolet divergences and mass factorization of infrared divergences in dimensional regularization through NNLO. We provide an extensive phenomenological analysis of the effects of NNLO corrections on SIDIS cross sections for different PDFs and FFs and various kinematics, including those of the future Electron-Ion Collider (EIC). We find that these corrections are not only significant but also crucial for reducing the dependence on the renormalization and factorization scales µR and µF to obtain stable predictions.

Speaker: Vaibhav Pathak (The Institute of Mathematical Sciences, Chennai)

Radcor_2025_Vaibhav.pdf

15:30 Soft and virtual corrections to semi-inclusive DIS up to four loops in QCD

We apply the threshold resummation formalism for semi-inclusive deep-inelastic scattering (SIDIS) to derive the soft and virtual corrections for the SIDIS cross section up to four loops in QCD. Using the recently computed next-to-next-to-leading order QCD corrections for the SIDIS cross section together with known results for the form factor and splitting functions in QCD up to four loops, we derive the complete soft and collinear contributions to the SIDIS coefficient functions at four-loop order. We also include systematically the next-to-leading power corrections, which are suppressed near threshold. The numerical analysis of the new four-loop corrections shows a small effect on the cross section underpinning the very good perturbative stability of the SIDIS process at that order in perturbation theory, including the reduced dependence on the renormalization and factorization scales $\mu_R$ and $\mu_F$.

Speaker: Saurav Goyal (The Institute of Mathematical Sciences, Chennai)

Radcor25_Saurav.pdf

14:30 → 16:00 Coral 2

14:30 Massive Quark Effects in two-loop Helicity Amplitudes for Diphoton Production

Diphoton production, owing to its clean experimental signature and excellent reconstruction capabilities, serves as a key process for precision studies at high-energy colliders. Given its importance on the experimental side, it is essential to include higher-order perturbative corrections on the theoretical side to match the experimental precision. In this talk, I will present the computation of two-loop helicity amplitudes in QCD for diphoton production via both quark and gluon-initiated channels, retaining full mass dependence of the internal heavy quark loop.

Speaker: Mandeep Kaur (IISER Mohali, India)

Radcor2025-Mandeep.pdf

15:00 Bottom quark contribution in H -> ZZ^* at O(\alpha \alpha_s)

We compute the mixed QCD-electroweak corrections of order ( \mathcal{O}(\alpha \alpha_s) ) to the partial decay width of the Higgs boson in the decay channel ( H \rightarrow ZZ^* ), considering two scenarios: (i) neglecting the internal light quark masses, and (ii) including them as small but non-zero parameters. In the latter case, we employ the method of differential equations to evaluate the relevant master integrals as a series expansion in the small quark mass parameter. We quantify the impact of both approximations on the decay width. These new results enable a state-of-the-art prediction at ( \mathcal{O}(\alpha \alpha_s) ) for the Higgs decay into four leptons.

Speaker: Warsimakram Imamsab Katapur

RADCOR2025_Warsimakram.pdf

15:30 Two-loop all-plus helicity amplitude for self-dual Higgs boson with four gluons

I will present the analytic computation of a five-point two-loop scattering amplitude of a self-dual Higgs and four gluons. We consider the all-plus helicity configuration in the leading-colour approximation, and we adopt the effective theory where the self-dual Higgs couples directly to gluons in the large top mass limit. In this configuration the tree-level amplitude vanishes, which enables one-loop like unitarity cuts to identify a compact analytic form for (poly)-logarithmic terms in the amplitude. Instead the rational contribution to the finite remainder is recovered from Feynman diagrams sampled over finite fields which allows us to tackle the algebraic complexity.

Speaker: Federico Ripani

RADCOR25_Ripani.pdf

16:00 → 16:30 Tea Break

16:30 → 18:00 Coral 1

16:30 NLO Deep Inelastic Scattering with massive quarks

Lepton-proton Deep Inelastic Scattering (DIS) is a fundamental process for both the strong and weak sectors of the Standard Model, playing a crucial role in the measurement of the parton distribution functions of the proton, one of the main goals of the EIC program. On the theory side, however, since the starting of the LHC operations, the community has been focused on QCD corrections to hadron-hadron collisions. The calculation of many relevant matrix elements and their inclusion into general-purpose Monte Carlo frameworks for precise simulation of DIS (lepton-parton) cross sections and distributions are still of interest. We present the implementation of Deep Inelastic lepton-proton scattering at NLO in QCD, with a massive quark pair in the final state. We deliver fully differential predictions with NLO QCD accuracy in various key kinematic observables.

Speaker: Aris-George-Baldur Spourdalakis (NSCR Demokritos)

Radcorr2025Spourdalakis.pdf

17:00 Beam Single Spin Asymmetries in SIDIS

We investigate beam single-spin asymmetries (SSAs) in semi inclusive deep inelastic scattering (SIDIS) using theoretical models that incorporate spin-momentum correlations relevant to beam SSAs. These studies aim to deepen our understanding of the underlying mechanisms in SIDIS and contribute to the broader phenomenology of transverse momentum dependent (TMD) distributions.

Speaker: Siddhesh Padval

RADCOR25_Siddhesh_Padval.pdf

16:30 → 18:00 Coral 2

16:30 Optimising Renormalisation with Emergent Supersymmetries

Higher loop renormalisation gets progressively more computationally demanding, especially for the case of Operator renormalisation, where the numerator structures for higher Melin moments get very complicated. Our approach of emergent supersymmetries allows us to exploit SUSY Ward Identities and reveal equations among Green's functions for non-supersymmetric theories. With these equations the number of integrals to be calculated can be reduced, leading to faster evaluations. Here we explore this approach for the Gross-Neveu-Yukawa model, with the future outlook of extending this approach to the more complicated case of QCD.

Speaker: Mrigankamauli Chakraborty

emg_susy_talk.pdf

17:00 Phenomenology of Matching Exponentiated Photonic Radiation to a Parton Shower in KKMChh

KKMChh adapts the soft photon exponentiation of the program KKMC, initially for electron-positron annihilation, to hadron collisions, where it must interface to a parton shower and parton distribution functions (PDFs) which may already include effects of QED radiation. We describe the NISR (negative initial state radiation) algorithm developed to consistently interface with PDFs including QED effects, and present results on its effect on some distributions of phenomenological interest.

Speaker: Scott Yost

KKMChh-Yost-RADCOR2025.pdf

17:30 Recent Developments in IR-Improved Amplitude-Based Resummation in Precision High Energy Collider Physics

We present recent developments in precision high-energy collider physics based on the IR-improvement of unintegrable singularities in the infrared regime via amplitude-based resummation in QED X QCD ⊂ $SU(2)_L X U_1 X SU(3)^c$. We focus on specific applications relevant to precision observables in LHC/FCC, LC, CLIC, CEPC, and CPPC physics, for which we present new results and some new issues.

Speaker: B.F.L. Ward

RADCOR2025.pdf

19:00 → 20:00 Appetizers

20:00 → 22:00 Conference Dinner

Wednesday 8 October

09:00 → 11:00 Kalinga

09:00 Method of regions for dual conformal integrals

We apply the method of regions to the evaluation of dual conformal integrals with small off-shellness. In contrast to conventional approach, where the separation of regions is performed via dimensional regularization breaking the dual conformal invariance (DCI), we use a sufficiently generic combination of dimensional and analytic regularizations which preserves the dual conformal invariance. Within this regularization (dubbed as DCI regularization), the contribution of each region becomes dual conformal invariant. We show that our method dramatically simplifies the calculations. As a demonstration, we calculate the slightly off-shell DCI pentabox integral. The contributions of all 32 regions appear to be expressible in terms of products/ratios of Γ-functions multiplied by some powers of DCI cross-ratios. Therefore, after removing the regularization, we obtain the final expression in terms of cross-ratios logarithms only. We have checked that our result for pentabox integral numerically agrees with the result of the recent Belitsky\&Smirnov paper [arXiv:2508.14298] which has essentially more complicated form.

Speaker: Roman Lee

LeeRADCOR-1.pdf

09:30 Phase-space integrals through Mellin-Barnes representation

We present a novel analytical approach to calculating phase-space integrals, crucial for precision in particle physics. We develop a method to compute angular components using multifold Mellin-Barnes integrals, yielding results in terms of Goncharov polylogarithms for integrals involving three denominators. Our results include expressions for massless momenta to $\mathcal{O}(\epsilon^2)$ and for massive momenta to $\mathcal{O}(\epsilon)$. We derive recursion relations that reduce integrals with higher powers of denominators to simpler ones. We detail how to combine the angular part with the radial one, which requires careful handling of singularities.

Speaker: Taushif Ahmed

radcor2025_taushif.pdf

10:00 Challenges in precision electroweak physics at future colliders

I will review the current challenges in precision electroweak physics at the forthcoming High-Luminosity phase of the CERN LHC and at perspective lepton colliders. Special emphasis will be given to the determination of the fundamental parameters of the Standard Model lagrangian and to the parameterization of new physics effects.

Speaker: Alessandro Vicini (Università degli Studi e INFN Milano (IT))

Vicini-Radcor2025.pdf

10:30 FCC precision requests: challenges for Monte Carlos and phenomenology tools

Precision requirements of the future accelerator experiments are defined, by the expected luminosity and detector details such as granularity, background subtractions or even unexpected dead detector cells. Keeping in mind such requirements precision tag, substantially better than 0.1%, must be achieved. That means that complete second order (two loop) electroweak effects have to be taken into account, issues of parametric ambiguities resolved and dominant effects of substantially higher than third order QED bremsstrahlung corrections with detector response taken into account. Advantages of fully differential Mote Carlo solutions such as of KKMCee are clear, but more inclusive solutions will be of great value as well. The fits with optimal variables will remain of importance even if Machine Learning solutions will be widely used. Question of combined theory an experiment expertise, especially for more complex solutions can not be ignored. All that points to exciting but challenging next years program for field theory predictions.

Speakers: Zbigniew Andrzej Was (Polish Academy of Sciences (PL)), Zbigniew Was

wasPuri.pdf

11:00 → 11:30 Tea Break

11:30 → 13:00 Kalinga: Online

11:30 3-Loop unpolarized and polarized heavy flavor corrections to DIS: single and two-mass contributions

The complete 3-Loop single and two-mass unpolarized and polarized heavy flavor corrections to the deep inelastic structure functions F_2 and g_1 are presented. The massive OMEs allow to lift the variable flavor number scheme to the level of three loop order.

Speaker: Johannes Bluemlein

RADCOR25.pdf

12:00 Gradient-flowed Operator Product Expansion without Infrared Renormalons

A long-standing problem concerns the question how to consistently
combine perturbative expansions in QCD with power corrections in the
context of the operator product expansion (OPE), since the former exhibit
ambiguities due to infrared renormalons, which are of the same order as
the power corrections. We propose to use the gradient flow time
$1/\sqrt{t}$ as a factorization scale and to express the OPE in terms of
IR renormalon-free subtracted perturbative expansions and unambiguous
matrix elements of gradient-flow regularized local operators. We show on
the example of the Adler function and its leading power correction from
the gluon condensate that this method dramatically improves the
convergence of the perturbative expansion. We employ lattice data on the
action density to estimate the gradient-flowed gluon condensate, and
obtain the Adler function with non-perturbative accuracy and significantly
reduced theoretical uncertainty, enlarging the predicitivity at low $Q^2$.

Speaker: Martin Beneke (Technische Universitaet Muenchen (DE))

radcorremote.pdf

13:00 → 14:30 Lunch

20:00 → 22:00 Dinner

Thursday 9 October

09:00 → 11:00 Coral 1

09:00 Elliptic leading singularities and canonical integrands

In the well-studied genus zero case, bases of dlog⁡ integrands with integer leading singularities define Feynman integrals that automatically satisfy differential equations in canonical form. Such integrand bases can be constructed without input from the differential equations and without explicit involvement of dimensional regularization parameter ϵ. We propose a generalization of this construction to genus one geometry arising from the appearance of elliptic curves. We argue that a particular choice of algebraic one-forms of the second kind that avoids derivatives is crucial. We observe that the corresponding Feynman integrals satisfy a special form of differential equations that has not been previously reported, and that their solutions order by order in ϵ yield pure functions. We conjecture that our integrand-level construction universally leads to such differential equations. Based on arXiv:2504.20897

Speaker: Vasily Sotnikov (University of Zurich (UZH))

sotnikov_RADCOR2025.pdf

09:30 Analytic computation of elliptic scattering amplitudes for phenomenological applications

Analytic computation of multi-loop Feynman integrals is crucial for the current era of precision physics. These analytic computations often bring us to intriguing algebraic structures which help in establishing deep connections with Mathematics. In this talk I will talk about some analytic computations of elliptic multi-loop Feynman integrals with their phenomenological applications in mind.

Speaker: Ekta Chaubey (University of Bonn)

Talk_Ekta_RADCOR.pdf

10:00 Canonical differential equations beyond polylogs

Feynman integrals whose associated geometries extend beyond the Riemann sphere, such as elliptic and Calabi–Yau, are increasingly relevant in modern precision calculations. They arise not only in collider cross-section calculations, but also in the post-Minkowskian expansion of gravitational wave scattering. A powerful approach to compute such integrals is via differential equations, particularly when cast in canonical form, which simplifies their ε-expansion and makes analytic properties manifest. In this talk, I will present a method to systematically construct canonical differential equations even for integrals that evaluate beyond multiple polylogarithms, including elliptic and Calabi–Yau, highlighting its utility in both quantum field theory and gravitational physics.

Speaker: Sara Maggio

RadCor.pdf

10:30 Analytical and numerical results for scattering amplitudes involving elliptic integrals

I discuss recent progress in the analytical computation of scattering amplitudes involving elliptic integrals. Thanks to recent developments in the study of elliptic Feynman integrals, it is possible to derive a canonical basis for the full system of master integrals associated with a given process. In particular, I present the application of a powerful method to the system of master integrals relevant to diphoton and dijet production with heavy-quark mass dependence, highlighting how obtaining solutions in terms of iterated integrals leads to significant simplifications at the amplitude level. Furthermore, I discuss how fast and efficient numerical evaluations in the physical region can be achieved by constructing series expansion representations of the full amplitude.

Speaker: Federico Coro

fcoro_radcor.pdf

09:00 → 11:00 Coral 2

09:00 Towards an OpenLoops+LTD automated generator

Loop-Tree Duality (LTD) has recently gained significant attention as a method for computing higher-order corrections to scattering processes. To explore its potential in collider phenomenology, we are developing an automated NLO event generator that combines LTD with the OpenLoops framework. Infrared singularities are locally canceled through a direct combination of real and virtual corrections, and predictions for IR-safe observables are computed in a general and flexible way. We present recent progress in the framework’s development and show numerical results. This work represents a key step towards NNLO automation.

Speaker: Gloria Bertolotti

RadCor25_GB.pdf

09:30 Towards two-loop EW corrections in OpenLoops

At energies above the Electroweak (EW) scale, higher-order EW corrections exhibit a logarithmic enhancement which is driven by the ratio of the typical scattering energy to the gauge-boson mass. At next-to-leading order (NLO) these corrections lead to factors amounting to several tens of percent in tails of kinematic distributions of crucial LHC processes, and still contribute a few percent at next-to-next-to-leading order (NNLO). As such, their inclusion is essential to reduce theoretical uncertainties arising from missing higher-order corrections. In this talk, I will review the key features of the algorithm implemented in OpenLoops (OL) for calculating one-loop EW corrections in the logarithmic Sudakov approximation, namely at next-to-leading logarithmic (NLL) accuracy, and present the status towards its extension to the two-loop level. This approximation efficiently implements the Denner-Pozzorini algorithm using an effective vertex approach, enabling to reproduce the full one- and two-loop results with percent-level accuracy while preserving tree-level computational complexity.

Speaker: Lorenzo Mai (Università di Genova & INFN Genova)

LM_RADCOR 2025 - Puri.pdf

10:00 McMule for Low-Energy Precision Processes

McMule is a Monte Carlo framework developed to tackle the low-energy precision frontier by providing QED radiative corrections to leptonic scattering processes up to next-to-next-to-leading order (NNLO). Beyond pure QED effects, McMule also accounts for electroweak contributions and non-perturbative hadronic effects. Recent developments have extended its capabilities to incorporate pion form factors and non-perturbative hadronic vacuum polarisation within loop processes, using a combination of OpenLoops and effective field theory methods. In this talk, I will present an overview of the project and highlight its applications.

Speaker: Sophie Kollatzsch (PSI)

kollatzsch-radcor.pdf

10:30 history in the Making: A Tool for NNLO Cross Sections

In this talk, I will introduce history, a novel tool for predicting fully differential cross sections at NNLO QCD accuracy using the Nested Soft-Collinear Subtraction scheme. I will highlight its flexibility and broad applicability to a wide class of color-singlet production processes at hadron colliders. As a first application, I will present results for associated Higgs production (VH), including observables that may be sensitive to BSM effects, while also giving a preview of other processes that can be tackled within the history framework. This versatility opens the door to precision studies across a range of Standard Model and potential BSM signatures.

Speaker: Lukas Simon (LPTHE - CNRS et Sorbonne Université)

presentation.pdf

11:00 → 11:30 Tea Break

11:30 → 13:00 Coral 1

11:30 Algorithmic construction of finite integrals in 4 dimensions

We present our algorithm to construct finite integrals in 4 dimensions. The integrals constructed this way are finite at the integrand level such that no sector decomposition is required for their numerical evaluation. We provide several examples to demonstrate the application of our algorithm.

Speaker: Bakul Agarwal

BA_RadCor-2025.pdf

12:00 Fast evaluation of Feynman integrals via numerical integration of differential equations

We revisit the idea of numerically integrating the differential form of Feynman integrals. With a novel approach for the treatment of branch cuts, we develop an integrator capable of evaluating a basis of master integrals in double and quadruple precision, with significantly smaller run times than other tools. This opens the door to evaluating higher complexity Feynman integrals on the fly in Monte Carlo generators, and enables a cheaper and easy to parallelize generation of grids for the topologies with prohibitive computational times. To test its performance, we build the differential equation for the pentagon functions in the process $e^+e^- \to \pi^+\pi^-\gamma$ at $O(\epsilon^2)$, and extend it to the case where the virtual photons acquire an auxiliary mass under the General Vector-Meson Dominance model. In general, the integrals depend on up to 9 complex kinematic variables and their evaluation times is $O(\text{ms})$. Furthermore, we test two families that appear in the production of $t\bar{t}+jet$ at two loops, achieving evaluation times in double precision in hundreds of milliseconds. We comment on the results and suggest room for improvement.

Speaker: Pau Petit Rosas

RadCor25.pdf

12:30 Evaluating Feynman Integrals in the Minkowski Regime without Contour Deformation

We present a method for rewriting dimensionally regulated Feynman parameter integrals in the Minkowski regime as a sum of real, positive integrands multiplied by complex prefactors. This representation eliminates the need for contour deformation, allowing for direct numerical or analytic evaluation of the integrals. Our approach is applied to integrals up to three loops, including cases with internal masses and off-shell external legs. The resulting expressions are suitable for evaluation using existing techniques, such as sector decomposition, where we observe performance gains of up to four orders of magnitude in certain cases.

Speaker: Anton Olsson (Karlsruhe Institute of Technology)

positive_Feynman_integrands.pdf

11:30 → 13:00 Coral 2

11:30 Recent progress in antenna subtraction at NNLO and N3LO

In this talk I will review recent developments in the antenna subtraction method for higher-order calculations in QCD. In particular, I will illustrate the definition and applications of generalized antenna functions for final-state radiation at NNLO and present the first N3LO differential calculation performed entirely with antenna subtraction for jet production at electron-positron colliders. Finally, I will discuss how the extension of generalized antenna functions at N3LO will allow to tackle more complicated processes at this perturbative order.

Speaker: Matteo Marcoli (University of Durham)

Marcoli_RADCOR.pdf

12:00 Extension of the CoLoRFulNNLO Subtraction Scheme: Latest Developments

Perturbative cross-sections in QCD are plagued by kinematic divergences. While UV divergences are systematically handled through coupling and field renormalization, IR divergences arising from soft and/or collinear partons—can be treated in multiple ways. One approach is the construction of a local subtraction scheme. In this talk, we present the extension of the CoLoRFulNNLO subtraction scheme to hadron-hadron collisions, focusing on the analytic computation of the subtraction terms for the production of a color-singlet final state to NNLO accuracy.

Speaker: Pooja Mukherjee (University of Bonn, Germany)

RADCOR_2025.pdf

12:30 $B_c \to \eta_c$ form factors at large recoil: Interplay of soft-quark and soft-gluon dynamics

At next-to-leading power Soft-Collinear Effective Theory suffers from endpoint divergent convolution integrals. While this difficulty has been overcome for a number of processes by employing novel refactorization-based subtraction techniques, this method appears to be inapplicable for hard exclusive processes. To gain insight into a proper factorization of their QCD dynamics, we use diagrammatic resummation techniques to derive the double-logarithmic series of the “soft-overlap” contribution to $B_c \to \eta_c$ transition form factors, assuming the scale hierarchy $m_b \gg m_c\gg \Lambda_{\rm QCD}$. We find that the leading double logarithms arise from a peculiar interplay of soft-quark “endpoint logarithms” from ladder diagrams with energy-ordered spectator-quark propagators, as well as standard Sudakov-type soft-gluon corrections. We elucidate the all-order systematics, and show that their resummation proceeds via a novel type of integral equations. As an independent cross-check of our prediction, we computed the three-loop hard-collinear contribution with modern multi-loop techniques, which is the only missing ingredient to restore the double logarithms at this order.

Speaker: Dennis Horstmann

HorstmannRadcor25.pdf

13:00 → 14:30 Lunch

14:30 → 16:00 Coral 1

14:30 Recursive reduction of two-loop tensor integrals

In order to meet the precision requirements for the LHC and future colliders, next-to-next-to-leading order corrections to a wide range of processes are essential, making general automated tools highly desirable. Extending the strategy of the widespread one-loop program OpenLoops to two loops, there are three major ingredients: process-dependent tensor coefficients, tensor integrals, and process-independent counterterms. In this talk I focus on the second part and present a new recursive algorithm to reduce arbitrary two-loop tensor integrals to scalar integrals numerically.

Speaker: Fabian Lange

RADCOR_Lange.pdf

15:00 Feynman Integral Reduction using Syzygy-Constrained Symbolic Reduction Rules

We present a new algorithm for integration-by-parts (IBP) reduction of Feynman integrals with high powers of numerators or propagators, a demanding computational step in evaluating multi-loop scattering amplitudes. The algorithm starts with solving syzygy equations in individual sectors to produce IBP operators that turn seed integrals
into IBP equations without artificially raised propagator powers. The IBP operators are expressed in terms of index-shift operators and number operators. We perform row reduction to systematically reshuffle the IBP operators and expose reduction rules with symbolic dependence on the powers of propagators and numerators. When this is insufficient, we produce more symbolic reduction rules by directly solving the linear system of IBP equations in which some propagator/numerator powers are kept symbolic. This linear system is kept small, as the equations are generated from a small set of seed integrals in the neighborhood of the target integral. We stress-test our algorithm against two highly non-trivial examples, namely rank-20 integrals for the double box with an external mass and the massless pentabox. As an application, we revisit the IBP reduction in a calculation of scattering amplitudes for spinning black hole binary systems, which involves two-loop Feynman integrals with complexity greater than 20, and achieve much faster IBP reduction than that of the original calculation.

Speaker: Sid Smith

Radcor 2025.pdf

15:30 Intersection Theory and Canonical Differential Equations

I will review recent developments using methods from intersection theory to find and study the canonical basis for Feynman integrals beyond multiple polylogarithms. In particular I will explain how the intersection matrix can "detect" a canonical basis and how this property can be used in practice to constrain the transcendental functions appearing in the solution. The focus will be kept on practical aspects and no prior knowledge of intersection theory is assumed.

Speaker: Sven Stawinski

Radcor_Stawinski.pdf

14:30 → 16:00 Coral 2

14:30 Three-Loop QCD corrections to the production of a Higgs boson and a Jet

Speaker: Xiang Chen

RADCOR2025_Xiang_Chen.pdf

15:00 An algorithm towards \varepsilon-factorising Feynman Integrals

Feynman integrals play a central role in precision studies with the QFT framework. However, their complexity explodes dramatically as the number of loops and kinematics grows. Recently, we have found an algorithm towards finding the \varepsilon-factorised differential equations of general Feynman integrals without specifying their related geometry. In this talk, I will sketch the idea of this algorithm and use the unequal-mass three-loop banana integrals as an example.

Speaker: Xing Wang

RADCOR2025_XingWang.pdf

15:30 Seeing Color Confinement with Energy Correlators

In this talk, I will introduce the idea of probing QCD non-perturbative dynamics through the lens of Energy Correlators, with a focus on their role in TMD dynamics, spectator fragmentation, and multi-Regge kinematics (MRK). I will also highlight the advantages of this approach compared to conventional q_T or jet-based measurements.

Speaker: Yu Jiao Zhu

16:00 → 16:30 Tea Break

16:30 → 18:00 Coral 1

16:30 Phase space for tests and applications of photos Monte Carlo

For simulations of radiative corrections in decays of particles and resonances, questions of systematic ambiguities become more and more demanding with improving precision. Photos Monte Carlo has two modes of operation. The one based on exclusive exponentiation, of a non-Markovian algorithm, starting from a Poissonian distribution of independent photons, is expected to provide the best physical precision. It is free of so called minimal generated photon energy bias. The same emission kernel can be used in mode where maximum photon multiplicity is fixed to 1 or 2. This operation mode is prepared for tests and comparisons with fixed order matrix element calculations. It is indispensable in ambiguities evaluation. In both cases algorithm phase space constraints are introduced iteratively.

Speaker: Ananya Tapadar (IFJ-PAN, krakow)

RADCORE2025.pdf

17:00 Numerical Evaluation of the Two-Loop Dark Matter Power Spectrum in the EFTofLSS

This talk focuses on the application of modern numerical perturbative methods, familiar from collider physics, to the precision frontier of cosmology. To match the accuracy of modern cosmological surveys, theoretical predictions from the Effective Field Theory of Large-Scale Structure (EFTofLSS) must be pushed to the two-loop level, a task for which purely numerical techniques are essential due to the absence of known analytic master integrals. I will present a robust numerical framework for computing these two-loop corrections. Its efficiency for cosmological parameter scans is achieved by decoupling the cosmology dependence from the loop integrations. We ensure the stability of the multi-dimensional Monte Carlo integration by treating UV and IR singularities locally, at the integrand level. The core of the method is to pre-compute a set of universal tensor integrals, which are then combined to produce predictions for any specific cosmology. This framework allows us to compute the renormalized two-loop dark matter power spectrum, which requires 13 counterterms, some necessarily non-local in time. Our work demonstrates a successful application of numerical perturbative techniques to cosmology, enabling precision parameter inference and establishing the foundation for two-loop computations of other observables, like the galaxy power spectrum.

Speaker: Andrea Favorito

PresentationRadCor.pdf

17:30 Effect of anomalous HHH coupling on the decay H → Z Z* → 4 charged leptons

We have computed the electroweak corrections to H → Z Z* → 4 charged leptons, including the effect of anomalous HHH coupling in the κ-framework. The results of this scaling are gauge invariant. We have computed the results for H → e +e −µ +µ − and H → e +e −e +e − processes. The corrections for both processes depend on the input parameter scheme. In the GF scheme, the electroweak corrections are about 1.26% for the H → e +e −µ +µ − and about 0.25% for the H → e +e −e +e − process. However, changing the κ from 4 to −4, the corrections vary from less than 1% to about −6%. We have plotted a number of kinematic distributions. The corrections over most of the phase space regions are similar. These large corrections can be used to put a bound on the HHH coupling. This can help in determining the structure of the Higgs potential.

Speaker: Biswajit Das (The Institute of Mathematical Sciences, Chennai)

h_to_4l_radcor_25.pdf

16:30 → 18:00 Coral 2

16:30 The Subleading Symphony: Universality at Next-to-Leading Power

Precise experimental data from the Large Hadron Collider and the lack of any persuasive new physics signature necessitate deeper understanding of the Standard Model. The scattering cross-sections in the threshold limit are plagued with Leading power (LP) and next-to-leading power (NLP) logarithms. Different method of resummation of LP logarithms are developed over the last three decades based on factorisation properties of soft gluon radiation. Precise prediction to match with the avalanche of experimental data also requires the resummation of NLP logarithms, as they have a sizeable numerical impact in the cross-section calculation. The behaviour of NLP logarithms for several colour singlet processes are well known in the literature, however, there is a scarcity of results when final state colour particles are involved in the scattering process. In this talk, I will introduce a novel method to compute NLP corrections using colour-ordered helicity amplitudes. I will then demonstrate the universality of NLP leading logarithms for the production of a colourless particle in association with a jet.

Speaker: Sourav Pal (Physical Research Laboratory)

radcor25.pdf

17:00 Power Corrections in N-Jettiness Slicing scheme

The N-jettiness slicing method has become a standard tool for precision QCD calculations over the past decade. However, achieving reliable numerical control requires the inclusion of power corrections beyond leading power. In this talk, I will present results on next-to-leading power (NLP) corrections for both zero-jettiness and 1-jettiness observables at next-to-leading order (NLO). I will outline how NLP corrections can be systematically computed and investigate whether the process independence observed at leading power extends to NLP for color-singlet final states. For the zero-jettiness case, I will present a master formula that captures both soft and collinear subleading contributions in a unified framework, allowing for efficient evaluation of power corrections in high-multiplicity processes. I will also present the first explicit NLP calculation for 1-jettiness at NLO, focusing on prompt photon production. This study reveals how jet clustering influences subleading contributions and can potentially act as a building block for power corrections for a generic N-jettiness variable. These results give key insights into the subleading contributions to the cross sections for slicing variables and the applicability of N-jettiness slicing in collider phenomenology.

Speaker: Prem Agarwal

RADCOR2025_Premf-1.pdf

17:30 Automated calculation of soft functions for non-global observables

Collider observables can broadly be grouped into two classes: global observables, like e.g. many event shapes, and non-global observables, whose defining property is that they are sensitive to radiation only in part of the phase space. Non-globality gives rise to a special type of large logarithm, whose resummation is more involved than resummation in the global case. A framework to resum these logarithms has been developed based on Soft-Collinear Effective Theory, which involves intricate factorisation theorems with ingredient functions of arbitrary final state hard multiplicities. In this talk I will present some progress towards automating the calculation of soft functions for non-global observables to second order in the strong coupling constant. I will focus in particular on subtleties arising from the two-emission contribution with one emission inside and one out of the measurement region, and on extensions to the uncorrelated emission case.

Speaker: Rudi Rahn (University of Vienna)

Radcor25_Rahn.pdf

20:00 → 22:00 Dinner

Friday 10 October

09:00 → 11:00 Kalinga

09:00 Endpoint factorization for semileptonic boosted and offshell top quark decays

I discuss a novel factorization formula for boosted double resonant top-antitop production in e+e- annihilation with a semileptonic top quark decay in the region where the b-jet invariant mass is small. The off-shell top quark state is defined through a measurement of the invariant mass of all particle in the top hemisphere w.r. to the thrust axis and the b-jet by all hadrons in that hemisphere. The factorization allows to sum all large logarithms involved in top production and decay. We define a new factorization function, called the ultra-collinear-soft function which encodes all non-factorizable effects associated to coherent soft radiation in the top rest frame arising from top production, propagation and decay.

Speaker: Andre Hoang

Hoang-topdecay.pdf

09:30 Numerical Techniques for Multi-Loop Amplitudes in QCD and Gravity

We present advancements on the numerical unitarity method for the calculation of phenomenologically relevant multi-loop scattering amplitudes in QCD and gravity for processes involving massive particles. Applications for the LHC and for gravitational wave observatories will be included.

Speaker: Fernando Febres Cordero

Radcor_Oct_2025.pdf

10:00 From vacuum amplitudes to qubits

I will present the latest developments in the Loop-Tree Duality (LTD), focusing on our proposal to assemble theoretical predictions for collider observables from vacuum amplitudes — i.e., scattering amplitudes without external particles. We will also demonstrate how to integrate the resulting expressions, which are well-defined directly in the four physical dimensions of the spacetime, in a quantum computer.

Speaker: German Rodrigo (IFIC UV-CSIC)

2025_10_RADCOR_rodrigo.pdf

10:30 Generalizing the nested soft-collinear subtraction scheme for NNLO QCD calculations

The computation of higher-order corrections is complicated by the presence of complicated infrared singularities, which must be isolated and cancelled in order to obtain a finite result. I will discuss progress towards a local, analytic and general treatment of infrared divergences using the nested soft-collinear subtraction scheme

Speaker: Raoul Horst Rontsch

roentsch_radcor2025.pdf

11:00 → 11:30 Tea break

11:30 → 13:00 Kalinga

11:30 Progress in 5-loop calculations

Speaker: Peter Marquard (DESY)

talk.pdf

12:00 New Bases for Feynman Integrals

New strategies for organizing bases of Feynman integrals hold promise for simplifying the presentation of results for scattering amplitudes. I discuss work on finding finite integrals, and on applying them to amplitude calculations. I will also discuss properties of these integrals within integration-by-parts systems.

Speaker: David Kosower

New Bases for Feynman Integrals (RADCOR 2025, Oct 10, 2025).pdf

New Bases for Feynman Integrals (RADCOR 2025, Oct 10, 2025).pptx

12:30 Improving integration-by-parts and differential equations

I will discuss how ideas from geometry help to improve Feynman integral reduction and the construction of epsilon-factorised differential equations. In particular, I will outline a systematic procedure to obtain an epsilon-factorised differential equation for any Feynman integral.

Speaker: Stefan Weinzierl

puri.pdf

13:00 → 14:30 Lunch