Probing beyond the Standard PRISMA Cluster of Excellence Model with - PowerPoint PPT Presentation

Physics Colloquium, GSI Helmholtzzentrum für Schwerionenforschung Darmstadt, 18 June 2019 Matthias Neubert Probing beyond the Standard PRISMA Cluster of Excellence Model with Flavor Physics Johannes Gutenberg University Mainz

Large Hadron Collider (LHC) at CERN LHCb ATLAS CMS ALICE M. Neubert — Probing beyond the SM with Flavor Physics 1

The Standard Model M. Neubert — Probing beyond the SM with Flavor Physics 2

The Standard Model Leaves several questions unanswered: Why is there more matter than antimatter? What is the dark matter made of? How is the electroweak scale stabilized? M. Neubert — Probing beyond the SM with Flavor Physics 3

The Standard Model Leaves many questions unanswered: Why is there more matter than antimatter? What is the dark matter made of? How is the electroweak scale stabilized? … M. Neubert — Probing beyond the SM with Flavor Physics 3

Beyond the SM? Increasing mass Previously expected Searches for region for heavy particles with new particles Experimentally excluded large couplings Decreasing coupling Terra incognita Searches for light particles with small couplings M. Neubert — Probing beyond the SM with Flavor Physics 4

SMEFT ❖ Direct searches for new heavy particles at LHC have so far not led to a discovery ❖ Indirect searches for heavy new physics should be analyzed in context of a systematic extension of the SM as an effective field theory: [Buchmüller, Wyler 1986; Grzadkowski, Iskrzynski, Misiak, Rosiek 2010] many 1 1 O ( D =5) O ( D =6) X L SMEFT = L SM + + + . . . W Λ 2 i Λ W i i =1 SM without Neutrino masses Generic new-physics neutrino masses and oscillations phenomena M. Neubert — Probing beyond the SM with Flavor Physics 5

SMEFT ❖ All new-physics scales probed so far are rather large: New-physics scale Order Observable for g=O(1) Neutrino D=5 Λ ~ 10 9 TeV oscillations D=6 Proton decay Λ ~ 10 12 TeV D=6 Flavor physics Λ > 1–10 5 TeV D=6 EWPT Λ > 1 TeV D=6 Higgs couplings Λ > 0.5–1 TeV M. Neubert — Probing beyond the SM with Flavor Physics 6

Beyond the SM ❖ No solution yet to hierarchy problem (SUSY ???) ❖ No answers yet to other big questions: Nature of Dark Matter? ‣ Origin of matter-antimatter asymmetry? ‣ Explanation of flavor puzzle? ‣ Dark energy/cosmological constant and strong CP problems ‣ ❖ While the field waits for clues, remarkable things are happening in the flavor sector! M. Neubert — Probing beyond the SM with Flavor Physics 7

B-meson flavor anomalies: Violations of lepton universality ? M. Neubert — Probing beyond the SM with Flavor Physics 8

M. Neubert — Probing beyond the SM with Flavor Physics 9

B-meson flavor anomalies ❖ Intriguing hints of anomalies in B decays entered stage starting in 2012 (R D , R D*; R K , R K*; P 5 ’, …) R D ( ∗ ) = Γ ( ¯ B ! D ( ∗ ) ⌧ ¯ ⌫ ) ⌫ ) ; ` = e, µ. Γ ( ¯ B ! D ( ∗ ) ` ¯ R K ( ∗ ) = Γ ( ¯ B → ¯ K ( ∗ ) µ + µ − ) Γ ( ¯ B → ¯ K ( ∗ ) e + e − ) ❖ If true, they would be hugely important for the future development of high-energy particle physics at large! ❖ In fact, their importance cannot be overstated … M. Neubert — Probing beyond the SM with Flavor Physics 10

B-meson flavor anomalies ❖ … because they would give a clear target for future searches at energy frontier! Increasing mass New physics cannot be Previously expected Searches for too far from here! region for heavy particles with new particles d e d large couplings u l c x e y l l a t n e m i r Decreasing coupling e p x E Terra incognita Searches for light particles with small couplings M. Neubert — Probing beyond the SM with Flavor Physics 11

Flavor anomalies: R D & R D* ❖ A totally unexpected signal of new physics in tree-level, CKM-favored, semileptonic decays of B mesons: b→clν →Dlν → u, Λ b →Λ c l ν � cays � R D ( ∗ ) = Γ ( ¯ B ! D ( ∗ ) ⌧ ¯ ⌫ ) � ⌫ ) ; ` = e, µ. Γ ( ¯ B ! D ( ∗ ) ` ¯ leptons � μ to determine the CKM elements ( ) very well, i.e. tree-level in � Δ M. Neubert — Probing beyond the SM with Flavor Physics 12