Annual Meeting of the CRC TRR 257

May 26, 2021, 12:00 PM → May 28, 2021, 4:30 PM Europe/Berlin

Michael Krämer (RWTH Aachen University)

The annual meeting of the CRC TRR 257 “Particle Physics Phenomenology after the Higgs Discovery'' will be held on May 26th-28th, 2021 

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The meeting will be held as an online event. Connection details will be provided in due course. 

Wednesday, May 26

1:00 PM → 1:30 PM Welcome

Speakers: Kirill Melnikov (TTP KIT), Michael Krämer (RWTH Aachen University)

1:30 PM → 3:30 PM CRC reports: Flavour

Convener: Alexander Lenz (Siegen University)

1:30 PM Project reports: SM flavour physics

Speaker: Tobias Huber (Siegen U)

sfbtrr257may21huber.pdf

2:30 PM Project reports: BSM flavour physics

Speaker: Ulrich Nierste (Institut fuer Theoretische Teilchenphysik, KIT CS)

nierste_bsm_flavour.pdf

3:30 PM → 4:00 PM Coffee break

4:00 PM → 5:00 PM Invited talks: Effective field theories

Convener: Kirill Melnikov (TTP KIT)

4:00 PM Effective field theories

Speaker: Matthias Neubert (Johannes Gutenberg-Universität Mainz)

Seminar.pdf

5:00 PM → 6:00 PM Young Scientists Forum: Part 1

Conveners: Elias Bernreuther (RWTH Aachen University), Martin Gabelmann (KIT), Oscar Cata

5:00 PM NLO QCD corrections for off-shell ttbb

I will present next-to-leading order QCD predictions for the process of top quark pair production in association with a b-jet pair at the LHC with center of mass energy of 13 TeV. In the calculation we concentrated on the di-leptonic decay channel of the top quark pair and we considered full off-shell effects. This study is particularly relevant for the measurements of the Higgs properties, because it represents a background to the Higgs production in association with a top quark pair. In addition, our predictions might be used for precise measurements of the top quark fiducial cross sections and to improve top quark decay modeling at the LHC.

Speaker: Michele Lupattelli (Aachen)

CRC2021_Lupattelli.pdf

5:20 PM ttW: Correlations and Asymmetries

The ttW^{+/-} process in the multi-lepton plus b-jet final state has shown discrepancies between experiment and theory as reported by the ATLAS collaboration. To this end, we employ NLO QCD off-shell results for this process to investigate the cross section ratio between ttW^+ and ttW^- which is a precision observable. Using these results we obtain theoretical errors of order 1%-2%, depending of the transverse momentum cut on the b-jet. Furthermore, motivated by this discrepancy we analyse the charge asymmetry of the top quark and it's decay products for this process. These are quite sensitive to the chiral nature of possible new physics in this channel. The theoretical uncertainty, modelling and reconstruction issues are addressed and discussed and finally we reach theoretical uncertainties of below 15% for this observable.

Speaker: Jasmina Nasufi (Aachen)

JasminaNasufi_CRC2021.pdf

5:40 PM NNLO QCD corrections to the B-meson mixing

In this talk I will discuss selected aspects of our calculation of the previously unknown NNLO QCD corrections to the $B_s - \bar{B}_s$ mixing process. These contributions are required to reduce the existing theory uncertainty on $\Delta \Gamma_{12}^s$, the flavor mixing parameter governing lifetime differences of neutral $B_s$ mesons.

Speaker: Vladyslav Shtabovenko (Karlsruhe)

shtabovenko-c1b_corr.pdf

6:00 PM → 7:00 PM Meeting of the principal investigators

Speaker: Kirill Melnikov (TTP KIT)

6:00 PM → 7:00 PM Meeting of the young scientists

Speakers: Elias Bernreuther (RWTH Aachen University), Martin Gabelmann (KIT), Oscar Cata

Thursday, May 27

9:00 AM → 11:00 AM CRC reports: BSM physics and methods/tools for precision calculations

Convener: Michal Czakon (RWTH Aachen University)

9:00 AM Project reports: BSM and dark matter at colliders

Speaker: Tilman Plehn (Heidelberg University)

transregio_21.pdf

10:00 AM Project reports: Tools and methods for precision physics

Speaker: Kirill Melnikov (TTP KIT)

CRC2021.pdf

11:00 AM → 11:30 AM Coffee break

11:30 AM → 12:30 PM Invited talks: Physics at future colliders

Convener: Dieter Zeppenfeld (KIT)

11:30 AM Physics at future colliders

Speaker: Michelangelo Mangano (CERN)

Mangano_CRC.pdf

12:30 PM → 2:00 PM Lunch break

2:00 PM → 3:20 PM Young Scientists Forum: Part 2

Conveners: Elias Bernreuther (RWTH Aachen University), Martin Gabelmann (KIT), Oscar Cata

2:00 PM Cornering the Two-Higgs-Doublet II Model

We perform a comprehensive study of the allowed parameter space of the Two-Higgs doublet model (2HDM) of type II. Using the theoretical framework flavio, we combine the most recent flavour, collider and electro-weak precision observables with theoretical constraints to obtain bounds on the mass spectrum of the theory. In particular we find that the wrong-sign limit is excluded and potential deviations from the alignment limit can only be small. Finally we test the consequences of our allowed parameter space on electro-weak baryo genesis via the programme package BSMPT.

Speaker: Matthew Black (Siegen)

Black.pdf

2:20 PM Top-quark fragmentation into a Higgs boson with next-to-leading order accuracy

We computed the tth fragmentation function at order O(yt2 αs). Real and virtual corrections have been computed by using modern loop computation techniques. In particular, we combined the unitary cut method with the differential equation approach. Moreover, we found a strategy for calculating the master integrals analytically, order by order in the dimensional regulator ε, in canonical basis.

Speaker: Colomba Brancaccio (Aachen)

Colomba.pdf

2:40 PM Top-Pair Events with B-hadrons at the LHC

In this talk, I will present NNLO QCD predictions for several differential distributions of B-hadrons in top-pair events at the LHC. Among other things, these predictions allow for a precise determination of the top-quark mass. The results also offer positive prospects for extracting heavy-flavour fragmentation functions from LHC data. On the technical side, I will demonstrate how to incorporate fragmentation in a subtraction scheme at NNLO.

Speaker: Terry Generet (Aachen)

CRC2021Generet.pdf

3:00 PM (g-2)𝜇, B anomalies and DM: a loop model tale

In this talk I will review how the anomalous magnetic moment of the muon and the B anomalies can be addressed by a combined explaination, by means of loop models characterized by minimal field content. Moreover, I will show how some of these model can also provide a viable DM candidate, accounting for the measured relic density while evading direct and indirect DM constraints.

Speaker: Marco Fedele (Karlsruhe)

CRC_Fedele.pdf

3:20 PM → 4:00 PM Coffee break

4:00 PM → 5:00 PM General assembly

Speaker: Kirill Melnikov (TTP KIT)

Friday, May 28

9:00 AM → 11:00 AM CRC reports: Higgs and collider physics

Convener: Gudrun Heinrich (Max Planck Institute for Physics)

9:00 AM Project reports: Collider phenomenology

Speaker: Malgorzata Worek (RWTH Aachen University)

Collider_Phenomenology-MWorek.pdf

10:00 AM Project reports: Precision Higgs physics

Speaker: Robert Harlander (RWTH Aachen University)

CRCHiggs.pdf

11:00 AM → 11:30 AM Coffee break

11:30 AM → 12:30 PM Invited talks: Cosmology and particle physics

Convener: Michael Krämer (RWTH Aachen University)

11:30 AM Cosmology and Particle Physics

Speaker: Geraldine Servant (DESY)

12:30 PM → 2:00 PM Lunch break

2:00 PM → 3:00 PM Young Scientists Forum: Part 3

Conveners: Elias Bernreuther (RWTH Aachen University), Martin Gabelmann (KIT), Oscar Cata

2:00 PM Exact top-quark mass dependence in hadronic Higgs production

The impact of the finite top-quark mass on the inclusive Higgs production cross section at higher perturbative orders has been an open question for almost three decades. I will report on the computation of this effect at NNLO QCD. This result eliminates one of the main theoretical uncertainties to inclusive Higgs production cross section at the LHC.

Speaker: Marco Niggetiedt (Aachen)

Niggetiedt.pdf

2:20 PM Third order corrections to the semi-leptonic $b\to c$ and the muon decays

In this talk we present our recent calculation of order $\alpha_s^3$ corrections to the semi-leptonic $b\to c$ and the muon decays. The calculation has been performed in an expansion around the heavy-daughter limit $m_c \sim m_b$, but also shows decent convergence for $m_c=0$ from which the contribution to the muon decay can be extracted.

Speaker: Kay Schoenwald (Karlsruhe)

Schoenwald.pdf

2:40 PM Automated calculation of beam functions in SCET

Over the last decades, factorization theorems became an important method to tackle problems in perturbative QCD, especially within the framework of effective field theories. In Soft-Collinear Effective Theory, these factorization theorems include beam functions accounting for the initial-state collinear interactions. While these functions have been calculated case by case for different observables until now, we are investigating an automated approach for a general class of observables. For this, we study a general phase-space parameterization which factorizes the singularities of the beam function in an universal way. This approach has been implemented in the public code "pySecDec" in order to calculate the next-to-leading order and part of the next-to-next-to leading order beam function.

Speaker: Marcel Wald (Siegen)

Talk_MarcelWald.pdf

3:00 PM → 4:00 PM Invited talks: Implicit bias in physics

Convener: Thomas Mannel (Siegen University)

3:00 PM Implicit bias in physics

Speaker: Marika Taylor (University of Southampton)

DFG.pdf

4:00 PM → 4:30 PM Concluding remarks

Speaker: Kirill Melnikov (TTP KIT)