Young Scientists Meeting 2026 of the CRC TRR 257

Sep 21, 2026, 9:00 AM → Sep 24, 2026, 4:20 PM Europe/Berlin

Houssem Amami (RWTH Aachen), Jaime del Palacio Lirola, Sauro Carlotti (KIT)

The Young Scientists Meeting is a meeting for all members of the Collaborative Research Center P3H (CRC TRR 257). The scientific talks will be presented by young scientists (PhD students or PostDocs) and they will focus on the various projects of our CRC. This will give all participants the opportunity to gain a better overview of these projects and allow the speakers to present their research in front of a large audience.

The talks will be around 15 minutes long, but the length might change slightly depending on the number of participants. The target audience of your talk will be your fellow PhD students and Postdocs.

The meeting also provides an excellent opportunity for scientific exchange between projects involved in several sites. Therefore every member of the CRC TRR 257 is invited to participate.

The Young Scientists Meeting 2026 will be held at RWTH Aachen University from September 21 - 24, 2026.

Abstract submission deadline: 05/09/2026

Registration deadline: 20/08/2026

Previous Meeting: https://indico.kit.edu/event/4941/overview

Following the Young Scientists Meeting, an Equal Opportunity Workshop will take place. Participants are encouraged to consult the dedicated section below for additional information.

Warning: Please beware! Some participants may receive fraudulent emails claiming to be from a company tasked with arranging accommodations for participants. These emails are scams.

---

 

 

Mon, September 21

12:00 PM Registration

Welcome Session

YSMeeting_Aachen2026.pdf

1 Senior Talk

Speaker: Michael Krämer (RWTH Aachen University)

2:00 PM Coffee break

Young Scientists Talks: Session 1

Convener: Alexander Mück (RWTH Aachen University)

2 Construction and Projection of Green's Bases for Effective Field Theories with AutoEFT

Effective field theories (EFTs) are an important tool in particle physics. They can be used both for describing the low-energy behavior of Standard Model processes, as well as for model-independent searches for BSM physics.

Working in an EFT requires a basis of independent operators. There are two types of bases: One is the so-called on-shell basis, where each Wilson coefficient is an independent parameter to the observables. The other basis is one of independent Green's functions. It contains additional operators and is required for calculations such as renormalization and RGE evolution, which happen at the level of Green's functions.

In this talk, I present a new version of the program AutoEFT that can construct both on-shell and Green's bases for EFTs. The algorithm supports EFTs with particles of spin $0$ and spin $1/2$, as well as gauge bosons of internal $\operatorname{SU}(n)$ and $\operatorname{U}(1)$ symmetries. A group-theoretical approach is used to determine the invariants of the Lorentz and gauge groups and to eliminate the redundancies between them.

Finally, I will explore how a projection algorithm for EFT operators can be implemented. A projection algorithm can be used to define an inner product on the vector space of EFT operators. This is important because the choice of basis operators is arbitrary, so different authors may be using different bases for their calculations. A projection algorithm will facilitate the translations of results between different bases.

Speaker: Lars Bündgen (RWTH Aachen University)

Präsentation_Bündgen.pdf

3 The goofy-symmetric Standard Model and the Hierarchy Problem

A new class of so-called "goofy" symmetries has been shown to lead to renormalization-group stable relations between parameters in two-Higgs-Doublet Models, not known before. In this work we investigate goofy transformations in the Standard Model (SM), extending them to the fermion sector. We show that the SM action is goofy "symmetric", if the Higgs mass term vanishes, while other SM interactions are allowed. Goofy symmetry could thus add another option to the very few means to successfully forbid the Higgs mass term, providing an alternative to conformal symmetry or shift symmetry. We further consider how electroweak symmetry breaking can be realized in the goofy symmetric SM via higher dimensional operators or an extended scalar sector. A viable Higgs mass can be obtained via spontaneous breaking of goofy symmetry, which can be realized via operators that would not be allowed by shift symmetry or conformal symmetry. We find that goofy-symmetric extensions of the SM are strongly constrained, but offer for example a straightforward dark matter candidate.

Speaker: Andrea Incrocci (KIT)

goofy_crc.pdf

3:20 PM Coffee Break

Young Scientists Talks: Session 2

Convener: Alexander Mück (RWTH Aachen University)

4 One-loop improved modelling of hadronic light-cone distributions amplitudes in HQET

Light-cone distribution amplitudes (LCDAs) parametrize the relevant hadronic information in factorization-based predictions for exclusive reactions with large energy/momentum transfer. A comprehensive theoretical understanding of these quantities is therefore essential to perform precision tests of the CKM mechanism in the Standard Model and to address currently observed flavour anomalies.
In this talk we focus on the LCDAs of heavy hadrons containing one heavy $b$-quark in the framework of heavy-quark effective theory (HQET). We explain how theoretical information about the so-called ''radiative tail'' in fixed-order perturbation theory can be consistently implemented in the construction of models or generic parametrizations of the LCDAs. As a specific example, we apply our approach to a generalized 3-particle LCDA of the $B$-meson, where the light quark and gluon field are separated along opposite light-cone directions, and briefly discuss the phenomenological relevance for rare exclusive $B$-meson decays.

Speaker: Daniel Vladimirov (University of Siegen)

VladimirovYSM26.pdf

5 Collinear Chiral Perturbation Theory

We construct Collinear Chiral Perturbation Theory, useful in the context of highly boosted pseudo-Goldstone systems, like heavy-to-light transitions at large meson recoil. We introduce the purely collinear Lagrangian based on two observations: A boosted Goldstone boson remains a low-virtuality degree of freedom, and the Lorentz contractions of the strong chiral Lagrangian pair its large light-cone derivative with a parametrically small one, so the boosted strong sector still follows the ordinary chiral expansion. External currents, however, are different: they supply a preferred light-like direction, so arbitrary $\bar n$ derivatives are unsuppressed and must be collected into light-ray operators. We build a tower of unsuppressed operators using the usual non-linear representation, but dressed with Wilson lines $\Sigma_\infty=W_{\ell_c}^\dagger\Sigma_c W_{r_c}$, where the Wilson lines are built from the external sources alone. By exploiting the unitarity of this field, we employ a subtraction procedure to arrive at a new basis that is triangular in collinear-meson multiplicity.

Speaker: Jaime del Palacio Lirola (University of Siegen)

SCChPT_YS.pdf

6 The $B^+-B^0$ Lifetime Differences @ NNLO

The total decay widths of heavy mesons can be systematically calculated in terms of an expansion in the two parameters $1/m_Q$ and $\alpha_s(m_Q)$, where $Q=c,b$ denotes the heavy quark. The dominant contributions to meson lifetime splittings stem from terms which are suppressed by $1/m_Q^3$ with respect to the leading universal contribution to the total decay width. We calculate three-loop contributions of order $\alpha_s^2/m_q^3$ to the lifetime ratios $\tau(B^+)/\tau(B_d^0)$, $\tau(D^+)/\tau(D^0)$, and $\tau(D_s^+)/\tau(D^0)$ in the limit of exact isospin and V-spin symmetry, respectively. Furthermore, we present new $\alpha_s/m_q^3$ corrections to the Cabibbo-suppressed terms in $\tau(B^+)/\tau(B_d^0)$.

Speaker: Francesco Moretti (TTP)

ysm26_moretti.pdf

6:00 PM Social Event - Tour of the old town

Tue, September 22

Young Scientists Talks: Session 3

Convener: Francesco Moretti (TTP)

7 The Short-Flow-Time Expansion of the Chromo-Magentic Dipole Moment Operator

Connecting low-energy lattice results to high-energy continuum calculations is highly nontrivial, since the two approaches rely on fundamentally different regularizations. The gradient flow offers an elegant way to bridge this gap: it can be implemented both on the lattice and in the continuum, and it has the useful property that composite operators built from flowed fields are UV finite after multiplicative renormalization.

In this talk, I will start by introducing the key concepts of the gradient flow. I will then discuss its application to the CP-even dimension-five operators of QCD, with particular focus on the chromo-magnetic dipole moment operator (CMDM). Afterwards, I will present the machinery and techniques used to relate the flowed CMDM to its unflowed counterparts, namely the short-flow-time expansion (SFTX). Finally, I will show parts of the resulting SFTX coefficients and discuss the flow-time evolution of the flowed CMDM, described by the flowed anomalous dimension.

Speaker: Lars Georg (RWTH Aachen University)

Presentation_YSM.pdf

8 Gradient Flow Integrals

The gradient flow has proved to be a versatile tool for perturbative lattice matching. Precision can only increase with computation cost. This requires optimisation of the tools used in calculations. We discuss the structure of integrals in the gradient flow and present GFReduce, a program for the analytic computation of any massless two-loop gradient flow bubble integral with the standard gradient flow gauge parameter $\kappa=1$. It makes use of direct integration and symmetries to minimise the number of sectors one has to consider before applying tailored integration-by-parts routines. In doing so we argue that the six known master integrals for this system are the only masters possible from physical calculations.

Speaker: Robert Mason (RWTH Aachen University)

GFIntegralsV2.pdf

10:30 AM Coffee Break

9 External speaker: The Ins and Outs of Moving In and Out of Academia

Speaker: Anders Rehult (QuTech, TU Delft)

rehult_aachen.pdf

12:00 PM Lunch

Young Scientists Talks: Session 4

Convener: Krzysztof Mekala (University of Siegen)

10 HISTORY: Fully Differential NNLO Predictions for the Standard Model and Beyond

In this talk, I will present HISTORY, a Monte Carlo event generator for computing fully differential cross sections for colour-singlet production in hadronic collisions up to next-to-next-to-leading order (NNLO) in QCD. HISTORY employs a process-independent implementation of the nested soft-collinear subtraction scheme, facilitating its extension to additional processes and models beyond the Standard Model through the incorporation of the relevant matrix elements. I will focus on recent developments, including new results for Higgs production through bottom–antibottom annihilation $\mathrm{b}\bar{\mathrm{b}} \to \mathrm{H}$, and discuss the extension of HISTORY from the Standard Model to the Minimal Supersymmetric Standard Model (MSSM).

Speaker: Houssem Amami (RWTH Aachen)

11 FeynGraph - A Modern High-Performance Feynman Diagram Toolkit

We present FeynGraph, a modern high-performance Feynman diagram generation toolkit designed to integrate seamlessly with modern computational workflows for calculating scattering amplitudes. FeynGraph is designed as a high-performance Rust library with easy-to-use Python bindings, allowing it to be readily used in other tools. With additional features like custom diagram selection filters, automatic diagram drawing, fully custom model format support through means of generic programming and automatic amplitude construction, FeynGraph strives to be a fully-featured Feynman diagram toolkit at any loop order.

Speaker: Jens Braun

CRC_FeynGraph.pdf

12 FeynCalc 10.2: This Is Why We Can Have Nice Things

In this talk we will discuss and demonstrate some new but lesser-known features of the recently released FeynCalc 10.2.1, such as parallel evaluation on multicore CPUs and tensor reduction with zero Gram determinants.

In addition to that, we will provide a sneak preview of upcoming functionality for manipulating multiple polylogarithms (HPLs and GPLs), making use of Mathematica 15's native support for these classes of functions.

Speaker: Vladyslav Shtabovenko (Uni Siegen)

talk-Shtabovenko.pdf

3:00 PM Coffee Break

Young Scientists Talks: Session 5

Convener: Vladyslav Shtabovenko (Uni Siegen)

13 A perturbative framework to probe infrared sensitivity in non-Abelian gauge theories

Understanding the infrared sensitivity of perturbative predictions in QCD is important for assessing the magnitude of possible non-perturbative power corrections to processes with large momentum transfer. In renormalon models, this sensitivity can be related to computable dependences of perturbative quantities on a small gluon mass. However, this procedure cannot be applied to collider processes with gluons at the Born level. To address this problem, we promote the gluon mass to a parameter of a consistent non-Abelian quantum field theory where the gauge symmetry is spontaneously broken through the Higgs mechanism. Working in the limit in which the gluon mass $m_g$ is the smallest dimensionful parameter, we compute through two loops the $\mathcal{O}(m_g)$ contributions to the relation between the pole and $\overline{\rm MS}$ masses of a heavy quark and to the relation between corresponding field counterterms. We also report on first steps towards applying this framework to computing $\mathcal{O}(m_g)$ contributions to top-pair production through two loops. We expect that the proposed framework will provide a useful laboratory for probing linear infrared sensitivity of this and other collider observables in QCD.

Speaker: Dennis Horstmann (KIT)

slides.pdf

14 A general subtraction formula at NNLO in QCD with massless partons

Beyond leading order in QCD, infrared singularities arise in real and virtual corrections and must cancel in physical observables. At NNLO, organising this cancellation becomes considerably more involved due to the presence of a myriad of unresolved limits. I will discuss how these can be systematically treated within the nested soft-collinear subtraction scheme for arbitrary processes with massless partons. This leads to a fully local, analytic and process-independent subtraction framework, in which the NNLO cross section is written in terms of explicitly finite contributions, completing the generalization of the scheme to arbitrary massless QCD processes at NNLO.

Speaker: Matteo Tresoldi

15 Soft gluon emission at two loops

In this talk, I will present the computation of the soft gluon emission at two loops. Such a limit is the only remaining unknown necessary for the construction of an N3LO subtraction scheme. Starting from two loops, two types of topologies contribute: the "dipole" which is already known up to the necessary order, and the "tripole", known in the literature up to O($\epsilon^0$). My work aims to be the first confirmation of the available results for the tripole, and its extension to O($\epsilon$).

Speaker: Marco Bigazzi (RWTH Aachen University)

Marco_bigazzi_CRC.pdf

7:00 PM Workshop Dinner

Wed, September 23

Young Scientists Talks: Session 6

Convener: Robert Mason (RWTH Aachen University)

16 Top quark mass effects in WW production through gluon fusion

The di-boson WW production is an important process for the precision tests of the Standard Model at the electroweak scale. In addition, it is one of the most significant backgrounds in the H→WW decay. While the gluon fusion production channel contributes only around 5% of the cross section, it is expected to receive sizable QCD corrections that will become significant during the High Luminosity phase of the LHC program. Moreover, its relative size is enhanced in the fiducial region of the H→WW decay. In this talk, I will discuss the computation of the helicity amplitudes of the gg→WW scattering.

Speaker: Mateusz Pawel Czaja (KIT TTP)

main.pdf

17 Complete NLO corrections to off-shell $t \bar{t}W^+$ production in the $2\ell SS$ channel

We present complete next-to-leading-order predictions for off-shell $t\bar{t}W^+$ production in the two-lepton same-sign channel at the LHC, considering the process

$pp\to \mu^+\nu_\mu\,e^+\nu_e\,b\bar{b}\,jj+X$

at a centre-of-mass energy of $\sqrt{s}=13.6~\mathrm{TeV}$. Finite-width effects of the top quarks and massive electroweak bosons are treated consistently, while doubly-resonant, singly-resonant and non-resonant contributions, together with all interference effects, are retained. The calculation incorporates the full set of Born contributions, ranging from $\mathcal{O}(\alpha_s^4\alpha^4)$ to $\mathcal{O}(\alpha^8)$, as well as all corresponding NLO QCD and electroweak corrections. This constitutes the first full off-shell NLO QCD calculation for the $2\ell\mathrm{SS}$ channel and, more generally, the first complete NLO prediction for this process. Results are presented for integrated and differential fiducial cross sections. Particular emphasis is placed on the impact of formally subleading perturbative contributions, which are found to induce sizeable effects in the integrated cross-sections and differential distributions. Their size, kinematic dependence and sensitivity to the adopted fiducial selection are investigated within the complete off-shell description of the process.

Speaker: Leon Mans (RWTH Aachen University)

ttw_complete_nlo.pdf

18 An analytical approach for the two-loop electroweak 𝑔𝑔 → 𝐻𝐻 amplitude

We present an analytical approach for the calculation of the top quark contribution to the two-loop electroweak 𝑔𝑔 → 𝐻𝐻 amplitude. The amplitude is considered in the forward limit, where the Mandelstam variable 𝑡 is small. We expand the amplitude at the level of the integrands and obtain good approximations for large parts of the phase space.

Speaker: Dominik Grau (KIT)

11:00 AM Coffee Break

Young Scientists Talks: Session 7

Convener: Humberto Reyes-Gonzalez (RWTH Aachen)

19 Conversion-Driven Baryogenesis with Quark-Philic Flavored Dark Matter

The origin of dark matter and the baryon asymmetry remains one of the central open problems in fundamental physics. Recent work has shown that lepton-flavored dark matter can naturally realize cogenesis of dark matter and baryons via conversion-driven freeze-out, where semi-efficient dark–visible conversions create a departure from equilibrium while thermalization of the dark sector erases any dependence on initial conditions.
In this talk, we extend this mechanism for the first time to quark-philic flavored dark matter, demonstrating that the viable parameter space is significantly enlarged up to the TeV scale. The enhancement arises from the stronger mediator coupling to quarks and the important role played by QCD bound-state formation during freeze-out. We further analyze the impact of finite-temperature corrections to decay and scattering rates, showing how they modify the thermal history and relic abundance across the parameter space. This scenario also predicts striking long-lived particle signatures with soft displaced decay products that remain only partially explored at the LHC and motivate dedicated searches at the HL-LHC.

Speaker: Lena Rathmann (KIT)

YSM2026_Rathmann.pdf

20 Kitchen Sink Anomaly Detection

Recent years have seen rapid progress in resonant anomaly detection for collider searches, but existing studies often rely on a limited set of signal benchmarks and face a trade-off between sensitive but model-dependent high-level observables and fully agnostic but less performant low-level representations. We address both limitations by introducing new simulated signal benchmarks, publicly released in a format compatible with the LHCO R&D benchmark, and by studying a broad high-level, yet highly agnostic, observable set combining Energy Flow Polynomials with subjettiness variables.
We evaluate this combined “kitchen sink” representation against several baseline observable sets in both an idealized anomaly-detection setting and the CWoLa hunting task. Across a broad range of signal types, the combined observable set achieves the best overall sensitivity.

Speaker: Lukas Lang (RWTH Aachen University)

YSM2026.pdf

12:30 PM Closing

12:50 PM Lunch

EDI workshops: Allyship / Inclusive Leadership

Convener: Felix Kahlhoefer (Karlsruhe Institute of Technology)

21 Allyship

Speakers: Helga Moser, Lena Fritsche

PPP_Allyship final.pdf

22 Inclusive Leadership

Speaker: Gesa Krämer

Inclusive Leadership Workshop Aachen.pdf

4:00 PM Coffee Break

EDI workshops: Allyship / Inclusive Leadership

Convener: Felix Kahlhoefer (Karlsruhe Institute of Technology)

Thu, September 24

EDI workshops: Allyship / Inclusive Leadership

11:00 AM Coffee Break

EDI workshops: Allyship / Inclusive Leadership

1:00 PM Closing