Challenges in Semileptonic B Decays

19 Apr 2022, 09:00 → 23 Apr 2022, 12:30 Europe/Zurich

Hotel Barolo -- Ristorante Brezza

Andreas Kronfeld (Fermilab), Christoph Schwanda (Austrian Academy of Sciences (AT)), Marcello Rotondo (INFN e Laboratori Nazionali di Frascati (IT)), Martin Jung (Università di Torino & INFN), Thomas Mannel (Siegen University), paolo gambino (università di torino)

Two of the elements of the Cabibbo-Kobayasha-Maskawa quark mixing matrix, |Vub| and |Vcb|, are extracted from semileptonic B decays. The experimental results, analysed in the light of the most recent theoretical calculations, remain puzzling, because — for |Vub| and |Vcb| — the exclusive and exclusive determinations are in tension. Furthermore, 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 Belle-II have the potential to resolve the issue in the next few years.

This workshop follows two previous workshops held at MITP (2015 and 2018) , sharing with them 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 expected luminosities and searching for ways to systematically validate the theoretical predictions in both exclusive and inclusive B decays.

In this workshop, scheduled originially for the spring of 2020 and now for spring 2022, 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, recent progress in lattice QCD, as well as the role played by QED radiative corrections.

The workshop will be held at Hotel Barolo, situated in the beautiful village of Barolo, surrounded by the amazing vineyard landscape of Piedmont Langhe-Roero and Monferrato, a UNESCO world heritage cultural site.

Hotel Barolo

Tuesday, 19 April

15:45 → 16:00 Coffee

16:00 → 17:30 Heavy to heavy exclusive: I

16:00 B to D(*) theory overview

Speaker: Danny van Dyk (TU München)

Challenges_in_Semileptonic_B_Decays_2022.pdf

16:30 B to D* form factors on the lattice I

Speaker: Alejandro Vaquero Avilés-Casco (University of Utah)

Barolo.pdf

17:00 Belle measurements of B to D(*) l v

Speaker: Manca Mrvar (Austrian Academy of Sciences (AT))

Barolo_workshop_exclusive.pdf

17:30 → 18:00 Break

18:00 → 19:00 Heavy to heavy exclusive: II

18:00 B->D* angular analysis in LHCb

Speaker: Lucia Grillo (University of Glasgow (GB))

Challenges_Semileptonic_lgrillo_v1.pdf

18:20 Vcb at LHCb with B and Bs decays

Speaker: Mirco Dorigo (INFN Trieste)

Vcb_Bs_challenges.pdf

18:40 Babar analyses

Speaker: Biplab Dey (Eotvos U.)

Biplab_Babar_v1.pdf

Wednesday, 20 April

09:30 → 11:00 Heavy to heavy exclusive: III

09:30 HPQCD calculations for H->H

Speaker: Judd Harrison

Judd_Harrison_HPQCD Heavy-Heavy decays.pdf

10:00 Vcb and R(D^(*)) using lattice QCD and unitarity

Speaker: Silvano Simula (INFN - Sezione di Roma Tre)

Barolo_Simula.pdf

10:30 R(D) and R(D*): status and prospects

Speaker: Gregory Max Ciezarek (CERN)

dtaunu_lhcb.pdf

11:00 → 11:30 Break

11:30 → 13:00 Heavy to heavy exclusive: IV

11:30 R(D)-R(D*) status and prospects at Belle

Speaker: Florian Urs Bernlochner (University of Bonn (DE))

Challenges_22.pdf

11:50 Semileptonic b decays at CMS

Speaker: Greg Landsberg (Brown University (US))

b->sll-Barolo.pdf

12:20 b-baryon semileptonic decays

Speaker: Patrick Haworth Owen (University of Zurich (CH))

baryonic_b_to_c.pdf

13:00 → 15:00 Lunch break

15:00 → 16:35 Heavy to heavy inclusive: I

15:05 Three loop calculations for inclusive semileptonic B decays

Speaker: Matteo Fael (KIT Karlsruhe)

Fael_Barolo.pdf

15:35 Inclusive Vcb

Speaker: Marzia Bordone (CERN)

bordone_barolo.pdf

15:55 q2 moments in the HQE

Speaker: Keri Vos (Universiteit Maastricht (NL))

Vcb_barolo.pdf

16:15 Inclusive semileptonic B decays at Belle (II)

Speaker: Raynette Van Tonder

Barolo2022_vanTonder_incl_clnu.pdf

16:35 → 17:00 Break

17:00 → 18:40 Heavy to light exclusive: I

17:00 Lattice calculations of exclusive b to u l v

Speaker: Oliver Witzel (Universität Siegen)

witzel_oliver.pdf

17:30 Fermilab update

Speaker: Aida El-Khadra

El-Khadra_Barolo2022.pdf

17:50 Light cone sum rules calculations for b to u channels

Speaker: Alexander Khodjamirian (University of Siegen)

Barolo_22.pdf

18:20 Fits for Vub exclusive

Speaker: Soumitra Nandi (University of Torino)

Nandi_2022_Barolo.pdf

Nandi_2022_Barolo.pptx

19:00 → 22:00 Aperitivo and dinner at the hotel

Thursday, 21 April

09:30 → 11:00 Heavy to heavy inclusive: II

09:30 JLQCD form factors for B-> D^(*) l v

Speaker: Takashi Kaneko

barolo_kaneko.pdf

10:00 Inclusive decays on the lattice

Speaker: Shoji Hashimoto (KEK)

Barolo2022-Hashimoto.pdf

10:30 Bs ->Xc l v at LHCb

Speaker: Marcello Rotondo (INFN e Laboratori Nazionali di Frascati (IT))

inclusive_bs_sl_lhcb.pdf

11:00 → 11:30 Break

11:30 → 13:00 Heavy to light exclusive: II

11:30 Bs -> K at LHCb

Speaker: Basem Khanji (Technische Universitaet Dortmund (DE))

Barolo_2022_BKhanji.pdf

11:50 Heavy to light exclusive at Belle (II)

Speaker: Christoph Schwanda (Austrian Academy of Sciences (AT))

vub_exclusive_schwanda.pdf

12:20 Probing the structure of the B meson with B to lll’ nu

Speaker: Aoife Bharucha (CNRS)

Aoife-Barolo.pdf

13:00 → 14:30 Lunch break

14:30 → 16:00 Heavy to heavy exclusive: guided discussion

Conveners: Andreas Kronfeld, Florian Urs Bernlochner (University of Bonn (DE)), Stefan Schacht (University of Manchester)

14:30 Discussion topics

Speaker: Stefan Schacht (University of Manchester)

discussion.pdf

15:30 Contribution to the discussion

Speaker: Silvano Simula (INFN - Sezione di Roma Tre)

discussion_Simula.pdf

16:00 → 16:30 Break

16:30 → 18:00 Heavy to heavy exclusive: Open discussion

16:30 B to D** ffs with LCSRs

Speaker: Nico Gubernari (Universität Siegen)

16:40 Dispersive matrix analysis of B to pi

Speaker: Ludovico VITTORIO (SNS, Pisa)

Barolo_Vub_LV.pdf

Barolo_Vub_LV.pptx

16:50 B to D* fits

Speaker: Martin Jung (Università di Torino & INFN)

18:00 → 19:00 Wine tasting

Friday, 22 April

09:30 → 11:00 Heavy to light inclusive

09:30 Inclusive charmless decays at Belle (II)

Speaker: Lu Cao (University of Bonn)

Barolo2022_LuCao.pdf

10:00 Inclusive theory overview

Speaker: Gil Paz (Wayne State University)

Vub_Theory_Apr_21_2022.pdf

10:30 Vub and radiative decays with SIMBA

Speaker: Zoltan Ligeti (Lawrence Berkeley National Lab. (US))

barolo.pdf

11:00 → 11:30 Break

11:30 → 13:00 Heavy to light inclusive

11:30 The spectrum of b->s gamma with neural networks

Speaker: Enrico Lunghi (Indiana University)

Lunghi-Barolo-NNbsgamma.pdf

11:50 Vub/Vcb inclusive at Belle

Speaker: Marcel Hohmann

barolo_2022_MHohmann.pdf

12:10 Subleading perturbative corrections

Speaker: Bernat Capdevila (University of Turin)

12:30 Testing New Physics in R(D(*)) at the LHC

Speaker: Ryoutaro Watanabe (INFN Pisa)

Barolo_Ryoutaro.pdf

13:00 → 15:00 Lunch break

15:00 → 16:30 QED corrections

15:00 The treatment of photons in experiments

Speaker: Florian Urs Bernlochner (University of Bonn (DE))

15:30 Playing with Photos

Speaker: Marcello Rotondo (INFN e Laboratori Nazionali di Frascati (IT))

16:00 Comments on Vub/Vcb from Bs->K

Speaker: Enrico Lunghi (Indiana University)

Comment on BsK - Lunghi.pdf

16:15 Discussion

Speaker: Stefan Schacht (University of Manchester)

16:30 → 17:00 Break

20:00 → 23:00 Workshop dinner

Saturday, 23 April

09:00 → 10:30 Future prospects

09:00 Prospects of lattice calculations

Speaker: Andreas Kronfeld

barolo.pdf

09:30 Experimental prospects at Belle II

Speaker: Christoph Schwanda (Austrian Academy of Sciences (AT))

belle2_prospects_schwanda.pdf

09:50 Experimental prospects at LHCb

Speaker: Concezio Bozzi (INFN Ferrara)