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The Superb Facility

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The Superb Facility More than just B physics! The SuperB Facility Adrian Bevan Edinburgh, 16th November 2007 Conceptual Design Report: arXiv:0709.0451 (hep-ex) http://www.pi.infn.it/SuperB/ Overview • Introduction • New Physics Search Capability • Accelerator Aspects • Detector Design • Summary • Conclusion November 2007 Adrian Bevan 2 http://www.pi.infn.it/SuperB/ Physics Case November 2007 Adrian Bevan 3 http://www.pi.infn.it/SuperB/ Data Sample • Aim: integrate 50-100 ab-1 of data (12ab-1/yr at design lumi). • Two orders of magnitude larger data set than the current B- factories: – i.e. 55-110 Billion BB pairs operating at the Y(4S). – Similar numbers of D mesons and τ leptons. – Can run at different √s, e.g. Y(5S) for Bs physics. • New concepts in accelerator technology should enable us to meet this target within 5 years of data taking. – Accelerator R&D is well underway at Frascati to test these concepts. • Timescale: Aim to start taking data 5 years after funding gets approved. November 2007 Adrian Bevan 4 http://www.pi.infn.it/SuperB/ Physics Case – in a Nutshell • We expect New Physics (NP) at the TeV scale: – Same motivation as the LHC! • This physics will have some kind of flavour structure: – Rich structure: we have to measure it! – Trivial structure: we have to confirm! • This new physics may, or may not help elucidate the matter- antimatter asymmetry problem. • SuperB can make complementary measurements to the LHC programme: – Many rare decay final states are only accessible to SuperB. – Sensitive to off-diagonal terms in the squark mixing matrix. – Test Lepton Flavour Violation (LFV) in τ decay. – Can study CP and CPT violation in τ decay, τ anomalous magnetic moment. – Search for CP (and CPT) violation in D decays. November 2007 Adrian Bevan 5 http://www.pi.infn.it/SuperB/ What do we mean by flavour Structure? • The relation ship between generations of particles (quarks, squarks, leptons). • Using quarks as an example: + qucti = ,, W V = g iVγ γ qdsbj = ,, 2 μ Lij These gauge interactions form a ⎛⎞VVV 3x3 unitary matrix called the Cabibbo- ud us ub Kobayashi-Maskawa CKM matrix. ⎜⎟ VV= VV ⎜⎟cd cs cb The CP conjugate interactions have couplings with factors of V *. ⎜⎟ ij ⎝⎠Vtd Vts Vtb November 2007 Adrian Bevan 6 http://www.pi.infn.it/SuperB/ Testing Flavour Structure • In addition to measuring rates of flavour changing transitions, we can probe flavour structure using asymmetry observables: NN− A = NN+ – Integrating over all signal events (e.g. B0→Kπ) – As a function of some kinematic variable (e.g. b→sll) – As a function of the time difference between a known flavour state decaying, and a tagged flavour state (neutral mesons only) (e.g. 0 B→J// ΨK S). BK0 → ±π ∓ B0 The difference between the blue and red curve indicates direct 0 CP violation in this particular B decay. November 2007 Adrian Bevan 7 http://www.pi.infn.it/SuperB/ hep-ex/0607106 Testing Flavour Structure • In addition to measuring rates of flavour changing transitions, we can probe flavour structure using asymmetry observables: NN− A = NN+ – Integrating over all signal events (e.g. B0→Kπ) – As a function of some kinematic variable (e.g. b→sll) – As a function of the time differenceThe shape and between features aof knownthe flavour state decaying, and a tagged flavourforward stat backwarde (neutral asymmetry mesons in only) (e.g. 0 B→J// ΨK S). B→K*ll is sensitive to new physics in FCNC. Solid line = SM prediction ~114 events Dotted line = sign flip C7 Dashed line = sign flip C9C10 Dot-Dashed line = sign flip both Phys.Rev.Lett. 96 (2006) 251801 Super B will probe K*e+e− final state to compliment K* μ+μ− from LHCb. Observables: Adrian Bevan November 2007 + − + − 8 fL, CP asymmetries,http://www. Api.infn.it/SuFB and B(seperB/e )/B(sμ μ ) Testing Flavour Structure • In addition to measuring rates of flavour changing transitions, we can probe flavour structure using asymmetry observables: NN− A = NN+ – Integrating over all signal events (e.g. B0→Kπ) – As a function of some kinematic variable (e.g. b→sll) – As a function of the time difference between a known flavour state decaying, and a tagged flavour state (neutral mesons only) (e.g. 0 B→J/ψK S). The sinusoidal oscillation indicates CP violation in this particular decay. Sine and Cosine amplitudes in this plot bccs→ decays indicate two different types of CP violation. November 2007 Adrian Bevan 9 http://www.pi.infn.it/SuperB/ hep-ex/0703021 Let’s put the existing programme into perspective • The current B factories have measured the unitarity triangle. – Both BaBar and Belle have outperformed expectations: • Observed CP violation in the B system, α & β • Evidence for oscillations in D system. • Measured the characteristics of the unitarity triangle beyond expectations. • Discovered a number of low energy hadronic states. • And performed a large number of other measurements besides this… with more than 540 publications since 1999. • The Tevatron has discovered mixing in Bs decays. • LHCb will start taking data soon, and will overconstrain the Unitarity Triangle. •So … … Standard Model tests will have been done to a high precision before a SuperB starts taking data. November 2007 Adrian Bevan 10 http://www.pi.infn.it/SuperB/ November 2007 Adrian Bevan 11 http://www.pi.infn.it/SuperB/ • Unitarity Triangle will be well measured before SuperB, and will be precision measurements at SuperB. •The angles and sides are calibration measurements, required in order to search for NP. November 2007 Adrian Bevan 12 http://www.pi.infn.it/SuperB/ November 2007 Adrian Bevan 13 http://www.pi.infn.it/SuperB/ New Physics Search Capability November 2007 Adrian Bevan 14 http://www.pi.infn.it/SuperB/ New Physics in Loops (ΔF=1) • Rare loop processes can have significant NP contributions. g~ b ss b ~ (δ d ) + RR 23 η’ bR φ,η′,(KK) 0 s~ g ss CP B R ss Ks0 ddd d KS • NP can modify the expected SM amplitudes and asymmetries. • Want to look in as many different modes (and with as many different observables) as possible. November 2007 Adrian Bevan 15 http://www.pi.infn.it/SuperB/ New Physics in Loops (ΔF=1) • βeff measured in b→s penguin decays can differ from β in b→ccs. Theory error on ΔS from penguin mode • Small uncertainties come from SM corrections to the decays. 0 – O(0.01) on sin(2βeff) in η’K 0 and 3K s. sin2β experimental Uncertainty. • Large deviations from SM W + expectation would indicate NP. ΔS – Discrepancyuc,,t decreases year QCDF: (Beneke, PLB620 (2005), SU(3): Grossman et al, PRD68 s 143-150, Cheng et al., PRD72 b φ,,()η′ KK (2003) 015004; Gronau et al, by year! CP (2005) 094003 etc. PRD71 (2005) 074019; …). 0 s SCET: (Williamson & Zupan, B g hep-ph/0601214) Can estimate ΔS and mostly see a d positive shift. • SuperB will be ables to probe0 KS these asymmetriesd on a mode- SM corrections to b→s penguin by-mode basis to the level of decays tend to prefer βeff > β. current SM uncertainties. November 2007 Adrian Bevan 16 http://www.pi.infn.it/SuperB/ New Physics in Loops (ΔF=1) • βeff measured in b→s penguin decays can differ from β in b→ccs. • Small uncertainties come from SM corrections to the decays. 0 – O(0.01) on sin(2βeff) in η’K and 0 3K s. • Large deviations from SM expectation would indicate NP. – Discrepancy decreases year by year! – Need to perform precision measurements on a mode-by- mode basis! • SuperB will be able to probe these asymmetries on a mode-by-mode basis to the level of current SM uncertainties (>50ab-1). November 2007 Adrian Bevan 17 http://www.pi.infn.it/SuperB/ New Physics in ΔF=2 Transitions 00 • ΔF=2 transitions in B ds ,, B ds systems are box diagrams (mixing or FCNC). qds= , q q • New physics (NP) can contribute with an amplitude ratio Cq and phase φq. 00 BqSMNPq||HB+ Ceiφq = q 00 BHqSMq|| B •Cq=1, and φq=0 for the Standard Model (SM). November 2007 Adrian Bevan hep-ph/0509219 18 http://www.pi.infn.it/SuperB/ New Physics in ΔF=2 Transitions 00 • ΔF=2 transitions in B ds ,, B ds systems are box diagrams (mixing or FCNC). qds= , q q • NP can contribute to these processes. – Parameterise with an amplitude ratio Cq and phase φq. 00 BqSMNPq||HB+ Ceiφq = q 00 BHqSMq|| B •Cq=1, and φq=0 for the SM. November 2007 Adrian Bevan hep-ph/0509219 19 http://www.pi.infn.it/SuperB/ New Physics in ΔF=2 Transitions • Existing measurements already constrain NP in Bd mixing. • SuperB will significantly improve this constraint. Current Constraint November 2007 Adrian Bevan hep-ph/0509219 20 http://www.pi.infn.it/SuperB/ New Physics in ΔF=2 Transitions • Existing measurements already constrain NP in Bd mixing. • SuperB will significantly improve this constraint. Current Constraint SuperB with 75ab-1 of data (includes expected improvements from lattice calculations) Note that the two plots have very different scales! November 2007 Adrian Bevan hep-ph/0509219 21 http://www.pi.infn.it/SuperB/ Minimal Flavour Violation • Suppose that there are no new physics flavour couplings (MFV). – CP violation comes from the known SM Yukawa couplings. – The top quark contribution dominates the SM. – NP contribution in ΔB=2 transitions is: SM Scale ~2.4 TeV 2 Λ=0 YMtWWsinθ /α 2 ⎛⎞Λ0 δ Sa0 = 4 ⎜⎟ ⎝⎠Λ Real Wilson coefficient O(1) New Physics Scale – MFV Includes many NP scenarios i.e. 1HDM/2HDM, MSSM, ADD, RS.
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