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Rare decays of B-mesons and the physics of the early Universe

English title Rare decays of B-mesons and the physics of the early Universe
Applicant Serra Nicola
Number 144674
Funding scheme SNSF Professorships
Research institution Physik-Institut Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Particle Physics
Start/End 01.07.2013 - 30.06.2017
Approved amount 1'515'061.00
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Keywords (6)

B-physics ; LHCb; Majorana Neutrino ; Rare Decays; Inflation; Particle Physics

Lay Summary (Italian)

Lead
Nonostante i notevoli progressi della fisica delle particelle elementari, numerose osservazioni astrofisiche e cosmologiche non si accordano con la nostra conoscenza della fisica fondamentale. Si tratta effettivamente di domande relative all'evoluzione dell'Universo, dalla sua fase primordiale ad alta energia a quella attuale di bassa energia. Misure di precisione di decadimenti rari di particelle note come "mesoni-B", potrebbero gettare nuova luce su tali affascinanti interrogativi.
Lay summary

La fisica delle interazioni fondamentali è descritta dal cosiddetto Modello Standard delle particelle elementari. Esso descrive con grande precisione tutti gli esperimenti di fisica sub-nucleare, ma non si accorda con alcune osservazioni astrofisiche e cosmologiche. Non spiega l’esistenza della “materia oscura”, né la rapida espansione iniziale dell’Universo, conosciuta come “inflazione”. Negli ultimi 20 anni c'è stata una notevole proliferazione di teorie alternative per cercare di risolvere queste lacune.

Queste teorie postulano l’esistenza di nuove particelle, che avrebbero giocato un ruolo essenziale nella fase primordiale, ad alta energia, dell’Universo. Tuttavia,  finora non esistono conferme sperimentali della correttezza di alcuna di queste teorie, né forti indizi che aiutino a discriminare quali fra esse siano più promettenti. 

L'obiettivo della nostra ricerca è di trovare possibili evidenze indirette dell'esistenza di tali particelle a livello microscopico, sfruttando effetti quantistici. Infatti, l'esistenza di nuove particelle massive può produrre effetti misurabili in decadimenti rari di mesoni-B, alterando per esempio la probabilità che tali decadimenti avvengano.

I mesoni-B sono formati da un quark ed un anti-quark, e vengono copiosamente prodotti nelle interazioni protone-protone  all'acceleratore LHC operante al CERN di Ginevra, in  cui è in funzione l'esperimento LHCb. Sfruttando l’alta precisione di questo esperimento nel misurare decadimenti dei mesoni-B,  ci proponiamo di testare numerose teorie proposte.

Questi studi potrebbero quindi contribuire a chiarificare aspetti fondamentali dell'evoluzione dell'Universo primordiale, e conseguentemente di quello attuale, ed eventualmente permettere una descrizione più completa della Natura. 


Direct link to Lay Summary Last update: 16.05.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
{Search for long-lived scalar particles in $B^+ \to K^+ \chi (\mu^+\mu^-)$ decays}
Aaij R. and others (2017), {Search for long-lived scalar particles in $B^+ \to K^+ \chi (\mu^+\mu^-)$ decays}, in Phys. Rev., D95(7), 071101.
Angular analysis of the $B^{0} \to K^{*0} \mu^{+}\mu^{-}$ decay using 3 fb$^{-1}$ of integrated luminosity
Aaij R et al. LHCb collaboraion (2016), Angular analysis of the $B^{0} \to K^{*0} \mu^{+}\mu^{-}$ decay using 3 fb$^{-1}$ of integrated luminosity, in JHEP, 02, 104.
Differential branching fraction and angular moments analysis of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the $K^*_{0,2}(1430)^0$ region
Aaij Roel and others (2016), Differential branching fraction and angular moments analysis of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the $K^*_{0,2}(1430)^0$ region, in JHEP, 12, 065.
Impact of leptonic $$\tau $$ τ decays on the distribution of $$B\rightarrow P\mu \bar{\nu }$$ B → P μ ν ¯ decays
Bordone Marzia, Isidori Gino, Dyk Danny van (2016), Impact of leptonic $$\tau $$ τ decays on the distribution of $$B\rightarrow P\mu \bar{\nu }$$ B → P μ ν ¯ decays, in The European Physical Journal C, 76(7), 360.
Observations of Λ0b→ΛK+π−Λb0→ΛK+π− and Λ0b→ΛK+K−Λb0→ΛK+K− decays and searches for other Λ0bΛb0 and Ξ0bΞb0 decays to Λh+h′−Λh+h′− final states
R. Aaij et al. LHCb Collaboration (2016), Observations of Λ0b→ΛK+π−Λb0→ΛK+π− and Λ0b→ΛK+K−Λb0→ΛK+K− decays and searches for other Λ0bΛb0 and Ξ0bΞb0 decays to Λh+h′−Λh+h′− final states, in JHEP, 1605, 081.
Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project
Britton T., Davis A., Dendek A., Dey B., Gandini P., Lionetto F., Manning P., Meadows B., Mountain R., Neri N., Petruzzo M., Pikies M., Skwarnicki T., Abba A., Artuso M., Blusk S., Ely S., Evans T., Fu J., Szumlak T., Wang J.C. (2016), Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project, in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detector, 806, 244-257.
Using Λb→Λμ+μ− data within a Bayesian analysis of |ΔB|=|ΔS|=1 decays
Meinel Stefan, van Dyk Danny (2016), Using Λb→Λμ+μ− data within a Bayesian analysis of |ΔB|=|ΔS|=1 decays, in Physical Review D, 94(1), 013007.
Extracting Angular Observables without a Likelihood and Applications to Rare Decays
Beaujean Frederik, Chrząszcz Marcin, Serra Nicola, Van Dyk Danny (2015), Extracting Angular Observables without a Likelihood and Applications to Rare Decays, in Physical Review, D(91), 114012.
LHCb Upgrade: Upstream Tracker
Lionetto Federica (2015), LHCb Upgrade: Upstream Tracker, in LHCb Upgrade: Upstream Tracker, PoS, PoS Vertex2014 (2015) 009.
Search for the lepton flavour violating decay τ−→μ−μ+μ−
Aaij Roel et al. (LHCb collaboration) (2015), Search for the lepton flavour violating decay τ−→μ−μ+μ−, in Journal of High Energy Physics, (02), 121.
Searches for low mass dark bosons
Mauri Andrea (2015), Searches for low mass dark bosons, in Searches for low mass dark bosons, PoS, PoS EPS-HEP2015 (2015) 536.
What Next: White Paper of the INFN-CSN1
F. Bedeschi et al. (2015), What Next: White Paper of the INFN-CSN1, in Frascati Physics Series, LX, 1.
Symmetry relations between angular observables in $B^0 \to K^* \mu^+\mu^-$ and the LHCb $P_5^\prime$ anomaly
Matias Joaquim, Serra Nicola (2014), Symmetry relations between angular observables in $B^0 \to K^* \mu^+\mu^-$ and the LHCb $P_5^\prime$ anomaly, in Phys. Rev., D90(3), 034002.
Symmetry relations between angular observables in $B^0 \to K^* μ^+μ^-$ and the LHCb $P_5^\prime$ anomaly
Matias Joaquim, Serra Nicola (2014), Symmetry relations between angular observables in $B^0 \to K^* μ^+μ^-$ and the LHCb $P_5^\prime$ anomaly, in Phys.Rev., D90(3), 034002-034002.
Measurement of Form-Factor-Independent Observables in the Decay $B^{0} \to K^{*0} μ^+ μ^-$
Aaij R, others (2013), Measurement of Form-Factor-Independent Observables in the Decay $B^{0} \to K^{*0} μ^+ μ^-$, in Phys.Rev.Lett., 111(19), 191801-191801.
Status of the scalar singlet dark matter model
Athron Peter et al., Status of the scalar singlet dark matter model, in European Journal of Physics.

Collaboration

Group / person Country
Types of collaboration
LHCb group, Imperial College of London, Prof. Ulrik Egede Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
B-physics Group, NIKHEF institute, Prof. Marcel Merk Netherlands (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
University of Milano Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Cracow Epiphany Conference 2017 Talk given at a conference Heavy-flavour highlights from LHCb 09.01.2017 Cracow, Poland Mauri Andrea;
BEACH 2016 Talk given at a conference Rare decays at LHCb 12.06.2016 George Mason University, Fairfax, Virginia USA, United States of America Silva Coutinho Rafael;
Experimental review of three body hadronic B meson decays Talk given at a conference FPCP 2016 06.06.2016 Caltech, Pasadena (CA), United States of America Silva Coutinho Rafael;
Prospects and challenges for semitauonic decays at LHCb Talk given at a conference SM predictions and uncertainties 27.04.2016 CERN, Geneva, Switzerland van Dyk Danny;
IFAE 2016 - XV Incontri di Fisica delle Alte Energie Talk given at a conference LHCb: test di universalita del sapore leptonico in decadimenti con elettroni e muoni nello stato finale 30.03.2016 Genoa, Italy, Italy Lionetto Federica;
125th LHCC Meeting Poster Search for hidden-sector bosons at LHCb 02.03.2016 CERN, Geneva, Switzerland Mauri Andrea;
Spring conference of the German Physical Society Talk given at a conference The impact of Lambda_b -> Lambda l^+ l^- in global fits of rare b -> sll decays 29.02.2016 Hanover, Germany van Dyk Danny;
610th WE-Heraeus-Seminar: 'Future Challenges in Non-Leptonic B Decays: Interplay between Theory and Experiment' Talk given at a conference B to pi pi form factors: Overview and Results at Large Dipion Masses 10.02.2016 Physikzentrum Bad Honnef, Germany van Dyk Danny;
5th Workshop on 'Implications from LHCb measurements and future prospects' Talk given at a conference The decay Lambda_b → Lambda(→ p pi) mu^+ mu^- 03.11.2015 CERN, Geneva, Switzerland van Dyk Danny;
5th Workshop on 'Implications from LHCb measurements and future prospects' Talk given at a conference Search for hidden-sector bosons in B0→K∗χ(→μμ) decays 03.11.2015 CERN, Geneva, Switzerland Mauri Andrea;
5th Workshop on 'Implications from LHCb measurements and future prospects' Talk given at a conference Non-lattice perspective on Vub and NP Searches 03.11.2015 CERN, Switzerland van Dyk Danny;
nuFact 2015 Talk given at a conference Heavy Neutrinos 10.08.2015 Rio de Janeiro, Brazil Serra Nicola;
DPF2015 Talk given at a conference Search for a light dark sector particle at LHCb 04.08.2015 University of Michigan, Michigan, United States of America Mauri Andrea;
EPS HEP2015 Talk given at a conference Searches for low mass dark bosons 22.07.2015 Vienna, Austria Mauri Andrea;
nuPhys 2014 Talk given at a conference Sterile GeV Neutrinos: Direct serches 15.12.2014 Queen Mary University, London, Great Britain and Northern Ireland Serra Nicola;
GDR Neutrino Meeting 2014 Talk given at a conference Searches for sterile neutrinos below the Electroweak Scale 27.11.2014 CPPM Marseille, France Serra Nicola;
VERTEX 2014 Talk given at a conference LHCb upgrade: Upstream Tracker 15.09.2014 Mácha Lake, Czech Republic Lionetto Federica;
Hadron Structure and QCD 2014 Talk given at a conference Associated vector boson production in the forward region 30.06.2014 St. Petersburg Nuclear Physics Institute, Russia Lionetto Federica;
Opening of the XXIX Ciclo of the PhD School in Physics Individual talk Favour Physics and the Search For New Physics 26.03.2014 University of Cagliari, Italy Serra Nicola;
EPSHEP 2013 Talk given at a conference Studies of electroweak penguin transitions of b->s mumu 18.07.2013 Stockholm University, Sweden Serra Nicola;


Self-organised

Title Date Place
Rare B Decays: Theory and Experiment 18.04.2016 Barcelona, Spain
Zurich Phenomenology Workshop 07.01.2015 University of Zurich, Switzerland
First SHiP Workshop 10.07.2014 Physik-Institute University of Zurich, Switzerland

Associated projects

Number Title Start Funding scheme
166915 FLARE 2016: Operation and upgrade of the LHCb experiment 01.04.2016 FLARE
155990 Search for hidden particles: exploring the high intensity frontier 01.01.2016 SNSF Starting Grants
173104 What's behind Flavour Anomalies? 01.07.2017 SNSF Professorships
173580 FLARE 2017-2020: Operation and upgrade of the LHCb experiment 01.04.2017 FLARE

Abstract

The interplay between cosmology and particle physics plays a key role in understanding the evolution of the Universe. Nevertheless, our knowledge of the early and the present Universe is far from complete. What is the nature of Dark Matter? How and why did the inflation of the Universe occur? An intriguing conjecture is that the study of rare decays of B mesons could cast new light on these big fundamental questions. I propose to use the largest existing sample of B-mesons, the one accumulated by the LHCb experiment to perform: Direct searches for new particles in rare semileptonic decays and indirect searches for new particles in the decays Bd->K*mu mu and Bs ->phi mu mu. If a signal is found, it will finally indicate a clear path that will lead future researches to the answer to these fundamental questions and to a more complete understanding of our Universe.
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