Ss2023
Fri, 26th May
- Time: 14:15
- Speaker: Syed Mehedi Hasan
- Title: Muon-electron scattering in the context of MUonE
Tue, 30th May
lecture free (Tuesday after Pentecost)
Fri, 2nd Jun
- Time: 14:15
- Speaker: Wolfgang Unger (Bielefeld)
- Title: Color Singlet Lattice QCD
Abstract
Lattice QCD in the dual variable approach is a method to circumvent the finite density sign problem. It also can be extended to incorporate the Strong Coupling Expansion. I review this representation in terms of color singlets, discuss ways to sample the partition function and show recent results on the nuclear transition. I also outline how this system can be studied on quantum computers and give first results on 2-dimensional lattices.Tue, 6th Jun
Fri, 9th Jun
Tue, 13th Jun
- Time: 15:15
- Speaker: Simon Pfahler (Master Vortrag)
- Title: Accelerating cancer progression model calculations using low-rank tensor networks
Fri, 16th Jun
- Time: 14:15
- Speaker: Mandeep Kaur
- Title: Analytical evaluation of multi-loop multi-scale Feynman integrals with massive or massless external lines
Abstract
Feynman integrals play a crucial role in perturbative quantum field theory calculations. Nowadays, there is active research focusing on the functions these integrals evaluate to, particularly in the context of multi-loop or multi-variable cases. In my seminar, I will discuss 2-loop integrals associated with 3-point topologies (planar with massive external lines) and 4-point topologies (non-planar with massless external lines), wherein the loop involves the top quark. I will provide a brief overview of the technical aspects involved in analytically evaluating these integrals using the DE method, as well as the basis functions they evaluate to.Tue, 20th Jun
- Time: 15:15
- Speaker: Jens Erler (Mainz)
- Title: A Tale with Precision
Abstract
The role of precision tests of the Standard Model is reviewed. Historically, they were key in establishing the theory and to verify its renormalizable structure, as well as the presence of radiative corrections. Today the emphasis has shifted to the determination of its parameters to very high accuracy and to searches for physics beyond the Standard Model. Some future prospects will also be discussed.Fri, 23rd Jun
Tue, 27th Jun
- Time: 15:15
- Speaker: Uli Haisch (Max Planck Institute, Munich)
- Title:Some applications of Standard Model effective field theory
Abstract
Maybe the new particles that address the open questions of the Standard Model such as the electroweak hierarchy problem, the flavour puzzle or dark matter are unfortunately too heavy to be directly produced at the Large Hadron Collider (LHC). In such a situation one can integrate out heavy degrees of freedom and describe new-physics effects in terms of Wilson coefficients of effective operators that appear in the SM effective field theory aka SMEFT. After briefly reviewing the status of global SMEFFT analyses at the LHC, I will discuss ways of how-to improve these fits with the goal to exploit the full potential of LHC in LHC Run III and beyond. First, I will highlight the important role that precision calculations play in constraining already well-bounded operators using the example of associated Zh production. Second, I will discuss a certain class of poorly bound interactions, namely third-generation four-quark SMEFT operators, and show that identifying and adding new observables with complementary sensitivities to the global SMEFT can be important.Fri, 30th Jun
- Time: 14:15
- Speaker: Andreas Juettner (CERN, Southampton)
- Title: Bayesian inference and QFT constraints for hadron physics
Abstract
In this talk I will discuss how Bayesian priors derived from first principles, for instance analyticity and unitarity, can be used to complement theory computations of hadron observables. I will demonstrate the ideas for the analysis of lattice-QCD simulations of exclusive as well as inclusive semileptonic B-meson decay. In the former case, the use of Bayesian inference allows for formulating a model- and truncation independent parameterisation of hadronic form factors. In the latter case, QFT priors allow to tackle the computation of the inclusive decay rate for the first time.Tue, 4th Jul
Fri, 7th Jul
- Time: 14:15
- Speaker: Nazario Tantalo (Roma II, ** ONLINE **)
- Title: Teaching to extract spectral densities from lattice correlators to a broad audience of learning-machines
Abstract
I will present a new method, developed in collaboration with M.Buzzicotti and A.De Santis and based on deep learning techniques, to extract hadronic spectral densities from lattice correlators. Hadronic spectral densities play a crucial role in the study of the phenomenology of strong-interacting particles and the problem of their extraction from Euclidean lattice correlators has already been approached in the literature by using machine learning techniques. In devising a new method the big challenge to be faced can be summarized in two pivotal questions: 1) is it possible to devise a model independent training strategy? 2) if such a strategy is found, is it then possible to quantify reliably, together with the statistical errors, also the unavoidable systematic uncertainties? We faced the challenge and our answers to these questions will be the subject of the talk.Tue, 11th Jul
- Time: 15:15
- Speaker: Margarita Garcia Perez (UAM, Madrid), ** ONLINE **
- Title: Large N in the box
Abstract
I will review some recent results on large N gauge theories obtained by exploiting the concepts of volume reduction and volume independence, and the special relationship between colour and space-time degrees of freedom that arises when gauge fields are formulated in a box with twisted boundary conditions.Fri, 14th Jul
- Time: 13:00 ** Note the earlier time (due to the Tag der Physik at 14:00)! **
- Speaker: Asmita Mukherjee (IITB, Mumbai)
- Title: Azimuthal asymmetries in back-to-back production of J/psi-jet and J/psi-photon at EIC
Abstract
We present a calculation of the above asymmetries using NRQCD for J/psi production. The asymmetries can help to probe the little known transverse momentum dependent gluon distributions in the proton at the future elecron-ion collider (EIC), in particular the linearly polarized gluon distribution for unpolarized proton, and gluon Sivers function when the proton in transversely polarized.Tue, 18th Jul
- Time: 15:15
- Speaker: Dominik Stöckinger (TU-Dresden)
- Title: Gamma5 in dimensional regularization - progress on non-anticommuting gamma5 and gauge-invariance restoration
Abstract
Gamma5 is notoriously difficult to define in D dimensions. The traditional BMHV scheme goes back to the earliest proposals by 't Hooft and Veltman and employs a non-anticommuting gamma5. Its advantage is full mathematical consistency and the existence of all-order proofs. Its disadvantage is the spurious breaking of gauge invariance in chiral gauge theories like the electroweak standard model. In our research programme we determine the required finite counterterms needed to restore gauge invariance, to allow more straightforward applications of the BMHV scheme in future practical calculations in the EWSM and beyond. In the talk we will first present the key ideas: definition of the problem and pedagogical explanations of breaking/restoration of gauge invariance. Then we outline the current status: the 2-loop treatment of an abelian chiral gauge theory like the U(1) sector of the EWSM, and the 1-loop treatment of a general Yang-Mills theory with fermionic and scalar matter.Fri, 21st Jul
Tue, 25th Jul
- Time: 15:15
- Location: ** Phy 9.2.01 **
- Speaker: Dhruv Sood (TIFR, Mumbai)
- Title: A Quantum Algorithm for Solving Linear Systems of Equations