Challenges in Semileptonic B Decays

Europe/Berlin
02.430 (Mainz Institute for Theoretical Physics, Johannes Gutenberg University)

02.430

Mainz Institute for Theoretical Physics, Johannes Gutenberg University

Staudingerweg 9 / 2nd floor, 55128 Mainz
Description

Two of the elements of the Cabibbo-Kobayasha-Maskawa quark mixing matrix, Vub and Vcb, are extracted from semileptonic B decays. The results of the B factories, analysed in the light of the most recent theoretical calculations, remain puzzling, because—for both |Vcb| and |Vub|—the exclusive and exclusive determinations are in tension by perhaps 3σ. This discrepancy could be an indication for New Physics. Further, measurements in the tau channels at Belle, Babar, and LHCb show discrepancies with the Standard Model predictions, pointing to a possible violation of lepton flavour universality. LHCb and the upcoming experiment Belle-II have the potential to resolve the issue in the next few years.

This workshop follows a first successful MITP workshop held in 2015, sharing with it the goal to develop a medium-term strategy of analyses and calculations aimed at solving the puzzles. We plan to have lattice and continuum theorists working together with experimentalists to discuss how to reshape the semileptonic analyses in view of the much higher luminosity expected at Belle-II, searching for ways to systematically validate the theoretical predictions in both exclusive and inclusive B decays, and to exploit the unexpectedly rich possibilities at LCHb.

In this second workshop, scheduled for the spring of 2018, we will focus on the expanding prospects of semileptonic decays at LHCb, on the implications of the first Belle-II data, on the possible violation of lepton universality, as well as on progress in lattice QCD, where first simulations treating b quarks like light quarks may become available.

Executive Summary (PDF)
Participants (PDF)
Program
    • Heavy to heavy excl. 02.430

      02.430

      Mainz Institute for Theoretical Physics, Johannes Gutenberg University

      Staudingerweg 9 / 2nd floor, 55128 Mainz
      • 1
        Introduction
        Speaker: Paolo Gambino (University of Turin)
      • 2
        B -> D(*) form factors from lattice QCD
        Speaker: Christine Davies (Glasgow)
        Slides
      • 3
        Vcb from B->D(*)lv and R(D,D*) predictions
        Speaker: Stefan Schacht (Torino)
        Slides
      • 4
        B->D** l v and its role in the extraction of Vcb and searches for new physics
        Speaker: Zoltan Ligeti (LBNL)
        Slides
      • 11:05
        Coffee break
      • 5
        Semileptonic B->D(*) decays at Belle/Babar and prospects @ Belle II
        Speaker: Phill Urquijo (Melbourne)
        Slides
      • 6
        Lambda_b -> Lambda_c(*) form factors from lattice QCD
        Speaker: Stefan Meinel (Arizona)
        Slides
      • 7
        Lambda_b semileptonic decays @ LHCb
        Speaker: Patrick Owen (Zürich)
        Slides
      • 13:00
        Lunch break
      • 8
        Discussion on exclusive heavy to heavy decays (combination of inputs from lattice and data, parametrizations, how to best perform exp analyses, status of LCSR,...)
        Speakers: Dr Christoph Schwanda (Institute of High Energy Physics, Austrian Academy of Sciences), Gregorio Herdoiza (Madrid)
    • Heavy to heavy with tau excl. 02.430

      02.430

      Mainz Institute for Theoretical Physics, Johannes Gutenberg University

      Staudingerweg 9 / 2nd floor, 55128 Mainz
      • 9
        Decays with taus @ LHCb
        Speaker: Greg Ciezarek (Nikhef)
        Slides
      • 10
        Decays with taus @Belle II
        Speaker: Giacomo Caria (Melbourne)
        Slides
      • 11
        How to diagnose NP in B -> D(*) tau nu
        Speaker: Martin Jung (TU Munich / Excellence Cluster Universe)
        Slides
      • 10:30
        Coffee break
      • 12
        Model independent constraints on new physics in semitauonic decays
        Speaker: Ben Grinstein (San Diego)
        Slides
      • 13
        Challenges for model builders from semileptonic anomalies
        Speaker: Dr Admir Greljo (JGU Mainz)
        Slides
      • 12:00
        Lunch break
      • 14
        Afternoon discussion on taus
        Speakers: Concezio Bozzi (Ferrara), Enrico Lunghi (Indiana/Torino)
    • 19:00
      Social dinner To be determined

      To be determined

    • b -> u/s exclusive 02.430

      02.430

      Mainz Institute for Theoretical Physics, Johannes Gutenberg University

      Staudingerweg 9 / 2nd floor, 55128 Mainz
      • 15
        Light Cone Sum Rules calculations for heavy to light form factors
        Speaker: Aoife Bharucha (Marseille)
        Slides
      • 16
        Lattice QCD predictions for heavy to light form factors (including K* challenges)
        Speaker: Prof. Aida El-Khadra (University of Illinois at Urbana-Champaign)
        Slides
      • 17
        Belle II prospects
        Speaker: William Sutcliffe (Karlsruhe)
        Slides
      • 10:30
        Coffee break
      • 18
        Measurements of Vub at LHCb
        Speaker: Marta Calvi (Milano)
        Slides
      • 19
        Discussion
        Speakers: Alexander Khodjamirian (Siegen), Lu Cao (Karlsruhe)
        Slides
      • 12:00
        Lunch break
      • 20
        Discussion on the report (outline, names, times)
        Slides
    • Inclusive b -> u 02.430

      02.430

      Mainz Institute for Theoretical Physics, Johannes Gutenberg University

      Staudingerweg 9 / 2nd floor, 55128 Mainz
      • 21
        Inclusive b -> u theory
        Speaker: Prof. Gil Paz (Wayne State University)
        Slides
      • 22
        Experimental status
        Speaker: Dr Marcello Rotondo (I.N.F.N. Padova)
        Slides
      • 23
        Status of SIMBA
        Speaker: Dr Florian Bernlochner (University of Bonn)
        Slides
      • 10:30
        Coffee break
      • 24
        B+ leptonic decays: review and prospects for Belle II
        Speaker: Youngjoon Kwon (Yonsei)
        Slides
      • 25
        Leptonic decays @ LHCb
        Speaker: Slavomira Stefkova (Imperial College London)
        Slides
      • 26
        Decay constants on lattice
        Speaker: Andreas Kronfeld (Fermilab)
        Slides
      • 12:30
        Lunch break
      • 27
        Afternoon discussion on inclusive Vub
        Speakers: Paolo Gambino (University of Turin), Vera Luth (SLAC - Stanford University)
        Slides
    • Inclusive b -> c 02.430

      02.430

      Mainz Institute for Theoretical Physics, Johannes Gutenberg University

      Staudingerweg 9 / 2nd floor, 55128 Mainz
      • 28
        Inclusive b -> c, also with taus
        Speaker: Thomas Mannel (Siegen)
        Slides
      • 29
        Heavy-quark masses and HQE matrix elements from Lattice QCD
        Speaker: Silvano Simula (Roma Tre)
        Slides
      • 30
        Inclusive rates from lattice
        Speaker: Shoji Hashimoto (KEK)
        Slides
      • 10:30
        Coffee break
      • 31
        Inclusive rates from lattice
        Speaker: Prof. Harvey Meyer (Joh. Gutenberg University Mainz)
        Slides
      • 32
        Experiment
        Speaker: Dr Christoph Schwanda (Institute of High Energy Physics, Austrian Academy of Sciences)
        Slides
      • 12:00
        Lunch break
      • 33
        Afternoon discussion on report etc
        Slides