Project

Back to overview

Physik der schweren Quarks

English title Heavy flavor physics
Applicant Greub Christoph
Number 137491
Funding scheme Project funding
Research institution Institut für Theoretische Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Theoretical Physics
Start/End 01.11.2011 - 31.10.2013
Approved amount 225'868.00
Show all

Keywords (5)

Determination of CKM matrix elements ; QCD corrections to electroweak processes; Rare B-meson decays; Renormalization group improvements; SUSY contributions to rare decays

Lay Summary (English)

Lead
Lay summary
This project deals with rare decays of B-mesons. These processes,
absent at the tree-level in the Standard Model (SM), are only induced
at the one loop-level where a W-bosons and a top-quark propagate
in the loop. In extensions of the SM, additional heavy particles can run
in the loop, which generate extra contributions to the decay
amplitudes of these decays. As these extra contributions are
generically as large as those from the SM, these processes are
very sensitive to new physics. To really establish deviations from the
SM, very accurate calculations are needed. In two sub-projects (A and B)
we refine the SM calculations for the branching ratios for b->s gamma
and  b->s gamma gamma, using techniques like decompositions into
master integrals (and differential equations to solve them).
The other three sub-projects (C, D and E) deal with calculations of various
observables in B-physics within the so-called MSSM, i.e., the minimal
supersymmetric extension of the SM. These three sub-projects aim at a better
understanding of the flavour structure of the MSSM. On the one hand,
our work will lead to more accurate limits on the parameter space of this
model. On the other hand, one can correlate the MSSM predictions for
rare decays and judge whether the MSSM could explain possible
deviations from the SM predictions.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Flavour-violation in two-Higgs-doublet models
Crivellin Andreas, Greub Christoph, Kokulu Ahmet (2014), Flavour-violation in two-Higgs-doublet models, in PoS, EPS-HEP2013, 338.
SUSY_FLAVOR library for rare decays in the MSSM
Crivellin Andreas, Rosiek Janusz (2014), SUSY_FLAVOR library for rare decays in the MSSM, in PoS, EPS-HEP2013, 081.
Contributions of the W-boson propagator to muon and tau leptonic decay rates
Ferroglia Andrea, Greub Christoph, Sirlin Alberto, Zhang Zhibai (2013), Contributions of the W-boson propagator to muon and tau leptonic decay rates, in Phys.Rev. D, 88(3), 033012-033012.
Flavor-phenomenology of two-Higgs-doublet models with generic Yukawa structure
Crivellin Andreas, Greub Christoph, Kokulu Ahmet (2013), Flavor-phenomenology of two-Higgs-doublet models with generic Yukawa structure, in Phys. Rev. D , 87(9), 094031-1-094031-37.
Tree-level contribution to \barB -> X_d gamma using fragmentation functions
Asatrian H.M., Greub C. (2013), Tree-level contribution to \barB -> X_d gamma using fragmentation functions, in Phys.Rev. D, 88(7), 074014-074014.
Two-loop SQCD corrections to Higgs-quark-quark couplings in the generic MSSM
Crivellin Andreas, Greub Christoph (2013), Two-loop SQCD corrections to Higgs-quark-quark couplings in the generic MSSM, in Phys. Rev. D, 87(1), 015013-015013.
Explaining $B\to D tau nu$, $B\to D^*tau nu$ and $B\to tau nu$ in a 2HDM of type III
Crivellin Andreas, Greub Christoph, Kokulu Ahmet (2012), Explaining $B\to D tau nu$, $B\to D^*tau nu$ and $B\to tau nu$ in a 2HDM of type III, in Phys.Rev. D, 86(5), 054014-054014.
Rare decays and MSSM phenomenology
Crivellin Andreas (2012), Rare decays and MSSM phenomenology, in Moriond EW 2012 proceedings, XY.
SUSY_FLAVOR v2: A Computational tool for FCNC and CP-violating processes in the MSSM
Crivellin A., Rosiek J., Chankowski P.H., Dedes A., Jaeger S., others (2012), SUSY_FLAVOR v2: A Computational tool for FCNC and CP-violating processes in the MSSM, in Comp. Phys. Commun., 184, 1004-1032.
Tauonic B decays in 2HDMs and the MSSM in the decoupling limit
Crivellin Andreas (2012), Tauonic B decays in 2HDMs and the MSSM in the decoupling limit, in PoS, CHARGED2012, 020-020.
The \bar{B} \to X_s γγdecay: NLL QCD contribution of the Electromagnetic Dipole operator O_7
Ahmet Kokulu (2012), The \bar{B} \to X_s γγdecay: NLL QCD contribution of the Electromagnetic Dipole operator O_7, in proceedings of SLAC eConf C120521, XY.
The MSSM with a Softly Broken U(2)^3 Flavor Symmetry
Crivellin Andreas, Hofer Lars, Nierste Ulrich (2012), The MSSM with a Softly Broken U(2)^3 Flavor Symmetry, in PoS, EPS-HEP2011, 145-145.
Flavor violation in the MSSM and implications for top and squark searches at colliders
Crivellin Andreas (2011), Flavor violation in the MSSM and implications for top and squark searches at colliders, in Frascati Phys.Ser., 54, 208-219.

Collaboration

Group / person Country
Types of collaboration
T. Hurth (Univ. Mainz) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
A. Ferroglia (New York City College of Technology) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Z. Zhang (The City University of New York) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
H. Asatrian (Yerevan Physics Institute) Armenia (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
A. Sirlin (New York University) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
J. Rosiek (University of Warsaw) Poland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
U. Nierste (Karlsruhe Inst. of Technology,KIT)) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
J. Kamenik (Jozef Stefan Institute, Ljubljana) Slovenia (Europe)
- in-depth/constructive exchanges on approaches, methods or results
L. Hofer (Univ. Wuerzburg) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
5th Bethe Center Workshop "LHC Run1 Aftermath: Where Theory Meets Experiment" Talk given at a conference The decoupling limit of the MSSM: the 2HDM of type III 30.09.2013 Bonn, Germany Crivellin Andreas;
EPS HEP 2013 "European Physical Society Conference on High Energy Physics" Talk given at a conference Flavour phenomenology of 2HDMs 17.07.2013 Stockholm, Sweden Crivellin Andreas;
Internationaler Workshop "Probing the Standard Model and New Physics at Low and High Energies" Talk given at a conference The MSSM in the decoupling limit 15.04.2013 Portoroz, Slovenia Crivellin Andreas;
Seminarvortrag an der University of Basel Individual talk Matching of the MSSM on the 2HDM 04.04.2013 Basel, Switzerland Crivellin Andreas;
Konferenz "Aspen 2013 - Higgs Quo Vadis" Talk given at a conference Flavour violation in 2HDMs 10.03.2013 Aspen, United States of America Crivellin Andreas;
Seminarvortrag an der Technical University of Munich Individual talk The MSSM in the decoupling limit 28.11.2012 München, Germany Crivellin Andreas;
Fourth International Workshop on Prospects for Charged Higgs Discovery at Colliders Talk given at a conference Tauonic B decays in THDMs of type III 08.10.2012 Uppsala, Sweden Crivellin Andreas;
CHIPP Annual Plenary Meeting Talk given at a conference LHC physics and indirect searches for new physics 13.09.2012 Kartause Ittingen, Switzerland Crivellin Andreas;
4th SuperB Collaboration Meeting Talk given at a conference New Physics effects in the determination of V_ub 31.05.2012 La Biodola (Elba), Italy Crivellin Andreas;
Konferenz "Flavour Physics and CP Violation" Poster The B->X_s\gamma\gamma decay: NLL QCD contribution of the electromagnetic dipole operator O_7 21.05.2012 Hefei, China Kokulu Ahmet;
Workshop "Fourth fermion generation and single-top production 2012" Talk given at a conference The Vub problem and single top production in the MSSM 26.03.2012 Leinsweiler, Germany Crivellin Andreas;
Seminarvortrag an der University of Warsaw Individual talk Flavour Physics in the MSSM 13.03.2012 Warschau, Poland Crivellin Andreas;
Konferenz "47th Rencontres de Moriond on Electroweak Interactions and Unified Theories" Talk given at a conference Rare decays and MSSM phenomenology 03.03.2012 La Thuile (Aostatal), Italy Crivellin Andreas;


Associated projects

Number Title Start Funding scheme
150057 Physik der schweren Quarks 01.11.2013 Project funding
124447 Elementarteilchenphysik und Feldtheorie 01.07.2009 Project funding

Abstract

The project on heavy flavour physics embraces a major direction ofresearch that will be under investigation at the Institute of Theoretical Physics at theUniversity of Bern. The research plan can be divided into two parts which contain the following subprojects: 1. Precision calculations in the standard modelA) B -> X_s gamma gamma at NLL precision in the SMB) New analysis of the branching ratio for B -> X_s gamma in the SM at NNLL precision 2. Phenomenological analysis in the minimal supersymmetric standard modelC) SQCD corrections to electroweak contributions to b -> s gamma in the unconstained MSSMD) The MSSM in the decoupling limit: A generic Two-Higgs-Doublet ModelE) Complete analysis of the MSSM flavour-structureThe goal of the first part is the precise calculation of the standardmodel contributions to these flavour-changing neutral current (FCNC) processes. This is important in order to identify possible new physics contributions. The second part aims on a better understanding of the flavour-structure of the minimal supersymmetric standard model (MSSM). On the one hand, this limits the allowed parameter-space of the MSSM which gives important constraints for model building. On the other hand one can correlate the MSSM predictions for rare decays and judge whether the MSSM could explain possible deviations from the SM predictions.
-