Neutral meson mixing and meson lifetimes are theory-side parametrised in terms four-quark operators which can be determined by calculating weak decay matrix elements using lattice QCD.
While calculations of meson mixing matrix elements are standard, determinations of lifetimes typically suffer from complications in renormalisation procedures because dimension-6 four-quark operators can mix...
We present new results for the Higgs production cross section in the gluon fusion channel at NNLO in QCD with the inclusion of top, bottom and charm mass effects. With these results one of the largest remaining uncertainties on the Higgs production cross section is eliminated.
Precise determination of hadronic matrix elements is crucial for interpreting possible deviations from the Standard Model observed in flavor physics experiments. While lattice QCD provides first-principles calculations, current results are still limited to a subset of the operators that may appear in theories of new physics. The sum rule approach employed here allows for a complementary...
The Heavy Quark Expansion has become the major tool for precision calculations for inclusive heavy hadron decays. The HQE is an expansion in $1/m_b$. Recently, moments of the dilepton spectrum of inclusive $B\to X_c\ell\bar{\nu}$ were used to precisely extract the CKM matrix element $V_{cb}$. Usually, one assumes that the charm quark is heavy, leading to...
We consider the next-to-leading order electroweak corrections to the Higgs boson pair productions in gluon fusion. This requires the computation of two-loop four-point amplitudes with massive internal particles such as top quarks, Higgs and gauge bosons. We perform analytic calculations both in the high-energy and large top-quark mass limits. In particular, we show that our high energy...
In this talk, I will present two improvements in the understanding of the non-factorizable corrections to Higgs production in VBF. One is to go beyond eikonal approximation and obtain the first power correction. Another is to address the problem of strong dependence on the renormalization scale of the leading eikonal corrections. The new sub-leading contribution will change the current...
In this talk we present the calculation of NLO QCD corrections to $pp\to t\bar{t}\gamma\gamma$ in the dilepton and lepton+jet decay channel. The top-quark and W-boson decays are performed in the narrow width approximation preserving spin correlations. We discuss the size of NLO QCD corrections at the integrated and differential fiducial level. In addition, we investigate the distribution of...
In this talk the $\mathcal{O}(\Lambda_{QCD})$ corrections to processes with top-quarks will be discussed. A general method to compute these corrections based on renormalon calculus and the Low-Burnett-Kroll theorem will be discussed. We will show that linear power corrections vanish for the total cross-section. We also compute such corrections to top-quark kinematic distributions and show...
In this talk, I will present NLO QCD results for the process $pp\rightarrow tt\overline{t}\overline{t}$, focusing on the 4-lepton channel at the LHC with $\sqrt{s}=13.6$ TeV. In our calculation, the top quark and the W boson are treated in the Narrow Width Approximation (NWA). We are analyzing our findings in two distinct situations: a full one where we have incorporated QCD corrections during...
While the knowledge of the leading-power behaviour of QCD amplitudes in the soft limit is crucial for the construction of subtraction schemes, next-to-leading power (NLP) results can be used to increase precision, which has successfully been applied to QED calculations. In this talk, I will present a universal expression for the soft limit of one-loop QCD amplitudes at NLP, that is, an...
We present a new version of pySecDec, a program to calculate multi-loop integrals numerically. The main theory and underlying algorithms will be explained, along with an overview of new features from the latest release. In addition, examples and timings for multi-loop integrals needed for LHC precision physics will be provided.
We present full off-shell NLO QCD results for $pp \to t\bar{t}W^+\, j+X$. We concentrate on the multi-lepton decay channel at the LHC with $\sqrt{s}= 13$ TeV. In our calculation off-shell top quarks and gauge bosons are described by Breit-Wigner propagators, furthermore, double-, single- as well as non-resonant top-quark contributions along with all interference effects are consistently...
The aim of our work is to explore the implications of the Baryogenesis model,
which is based on the B-Mesogenesis paradigm proposed by G. Elor, M. Escudero, and A. E. Nelson, on the phenomenological observables of the Bmeson. Specifically, we focus on analyzing the non-standard decay channels of the B-meson into a SM baryon and a dark sector antibaryon, which were proposed by the model to...
Theoretical calculations for Higgs-related processes at the LHC have reached an impressive level of accuracy. One of the technical challenges that still need to be addressed is the computation of two-loop box diagrams with massive internal lines, e.g. those arising in the NLO QCD corrections for $gg \to ZH$ and $gg \to ZZ$.
In this talk I will present a method for approximating these diagrams...
The status of Higgsstrahlung and single Higgs production cross-section predictions with the program SusHi is presented. It includes predictions in the Standard Model but also other models like the MSSM. A discussion of the calculation of total cross sections is followed by a description of the calculation of the invariant mass distribution of the Higgsstrahlung cross section. Lastly, methods...
Leptonic decays of neutral B mesons provide an excellent probe of physics beyond the Standard Model, due to the absence of tree-level flavour-changing neutral currents in the Standard Model and the corresponding smallness of the branching ratio. We present a two-Higgs-doublet model in which flavour-changing neutral Higgs couplings to up-type quarks can lift part of the SM suppression. The...
In this talk I present new constraints on the axion-nucleon coupling $g_{aNN}$ for massive ALPs using SN1987A. Standard arguments that restrict the energy loss of core-collapse supernovae are used, and novel bounds from modern water Cherenkov detectors are derived for axion masses in the MeV range. Recasting the invisible nucleon decay data of SNO+, a new exclusion limit can be found in the...
Axion-like particles (ALPs) arise in BSM theories with global symmetry breaking. Beam-dump experiments have been constructed and proposed to look for them at the sub-GeV scale. Given a successful signal observation, would we be able to reconstruct the ALP properties even from inaccurate detectors? We use a simulation-based inference approach to reconstruct the posterior probability of the ALP...
Weakly supervised methods have emerged as a powerful tool for model agnostic anomaly detection at the LHC. While these methods have shown remarkable performance on specific signatures such as di-jet resonances, their application in a more model-agnostic manner requires dealing with a larger number of potentially noisy input features. We show that neural networks struggle with noisy input...
Autoencoders are an effective analysis tool for model-agnostic searches at the LHC. Unfortunately, it is known that their OOD detection performance is not robust and heavily depends on the compressibility of the signals. Even if a neural network can learn the physical content of the low-level data, the gain in sensitivity to features of interest can be hindered by redundant information already...
Exclusive $B$-decays are sensitive to contributions from new physics and can thus be used to test the Standard Model. At large hadronic recoil Soft-Collinear Effective Theory is the appropriate theory to describe the QCD dynamics and to resum logarithmic corrections to all orders in perturbation theory. However, since the relevant hadronic matrix elements are power suppressed, the...
Recent examinations of the semileptonic charged-current have underscored discrepancies with the Standard Model, particularly in the Cabibbo Angle Anomaly, which demonstrates a 3-sigma deviation. We undertake a rigorous analysis using SMEFT to shed light on potential BSM sources of the Cabibbo anomaly. By integrating Collider processes, Low-energy processes, and EWPO, we establish a holistic...
