Flavor Physics at ee Colliders Botjan Golob University
Flavor Physics at e+e- Colliders Boštjan Golob University of Ljubljana/Jožef Stefan Institute & Belle/Belle II Collaboration Status & Plans Examples of measurements University of Ljubljana “Jožef Stefan” Institute Summary Alps 2017: an Alpine LHC Physics Summit Obergurgl, April 2017 B. Golob, Belle II 1/19
Status Inclusive Neutrals Summary Emiss e+ e- Status Accelerators? VEPP-4 M LEP(2) PEP-II CESR-C BEPC-II DA NE Super. KEKB Eastbound → considering acc. relevant (subjective) to this talk → Far East Obergurgl, April 2017 B. Golob, Belle II 2/19
Status Inclusive Neutrals Summary Emiss Status Accelerator “Super. KEKB” Tokyo (40 mins by Tsukuba Exps) Super. KEKB: e- (HER): 7. 0 Ge. V e+ (LER): 4. 0 Ge. V ECMS=M(U(4 S))c 2 (→BB) [M(U(1 S))c 2 , M(U(6 S))c 2] LER e- HER Belle 2 d. Nf / dt = s(e+e-→f)L L =8 x 1035 cm-2 s-1 e+ Obergurgl, April 2017 B. Golob, Belle II 3/19
Status Inclusive Neutrals Summary Emiss Status Accelerator “BEPC - II” BEPC-II: ECMS=2. 0 – 4. 6 Ge. V M(y(3770))c 2, M(y(4040))c 2 (→DD) (→DD*) L =1 x 1033 cm-2 s-1 Obergurgl, April 2017 B. Golob, Belle II 4/19
Status Inclusive Neutrals Summary Emiss Status Super KEKB luminosity planning 5 ab-1 Phase 1 35 ab-1 Phase 2 QCS, Belle 2 50 ab-1 Phase 3 VXD 20 ab-1 Phase 1: w/o QCS w/o Belle 2 Phase 2: w/ QCS w/ Belle 2 (no VXD) Phase 3: full Belle 2 http: //lhc-commissioning. web. cern. ch/lhc-commissioning/schedule/LHC%20 schedule%20 beyond%20 LS 1%20 MTP%202015_Freddy_June 2015. pdf Obergurgl, April 2017 B. Golob, Belle II 5/19
Status Inclusive Neutrals Summary Emiss Belle 2 planning Status Final focusing 150 Ge. V superconducting Cosmic ray in magnets ECL BEAST PHASE I: Simple background commissioning detector (diodes, TPCs, crystals). No final focus (i. e. no luminosity, single beam background studies possible). Feb – Jun 2016 Oct 2017 – Jan 2018 BEAST PHASE II: More elaborate inner background commissioning detector & full Belle II outer detector. Superconducting final focus, no vertex detectors. Physics Running Obergurgl, April 2017 Oct 2018 → B. Golob, Belle II 6/19
Status Inclusive Neutrals Summary Emiss Status Belle 2 Roll-in (April 11 th) es lin m a e ob t CDC Oct 2016 Obergurgl, April 2017 B. Golob, Belle II 7/19
Status Inclusive Neutrals Summary Emiss Status Belle 2 Roll-in (April 11 th) after 1 minute 30 seconds Obergurgl, April 2017 B. Golob, Belle II 8/19
Status Inclusive Neutrals Summary Emiss Status Belle 2 Roll-in (April 11 th) Obergurgl, April 2017 B. Golob, Belle II 9/19
Inclusive Neutrals Summary Emiss Status Properties of e+e- Colliders (as compared to LHC) • low energy A. Bondar et al. , Belle 2 -note-ph-2015 -003 e: g. A‘ coupling Status 10 -1 D. Curtin et al. , ar. Xiv: 1412. 0018 10 -2 10 -3 10 -1 Obergurgl, April 2017 1 10 100 B. Golob, Belle II 10/19
Status Inclusive Neutrals Summary Emiss Status Properties of e+e- Colliders (as compared to LHC) • low energy • low trigger rate / Event size (30 k. Hz 1 st level, 5 k. Hz high level; 300 k. B event size) • low multiplicity (O(10)) Obergurgl, April 2017 B. Golob, Belle II 11/19
Status Inclusive Neutrals Summary Emiss Status Properties of e+e- Colliders (as compared to LHC) • low energy • low trigger rate / Event size (30 k. Hz 1 st level, 5 k. Hz high level; 300 k. B event size) • low multiplicity (O(10)) • good hermiticity Missing E • specific methods for (n ) full event reconstruction fully (partially) reconstruct Btag; reconstruct h from e. g. Bsig→hnn or Bsig→ t(→ hn)n; no additional energy in EM calorim. ; signal at EECL~0; Btag full reconstruction (Neuro. Bayes) Obergurgl, April 2017 Btag Bsig → tn candidate event B. Golob, Belle II 12/19
Introduction Plans Emiss Inclusive Neutrals Summary Plans Lumi ratio for same sensitivity B → f. Ks B → J/y. Ks Belle II B-tagged LHCb Hadronic B → tn Belle 2 Ee+beam boost Relative yield increase Ee-beam from U(4 S) mass B. Golob, K. Trabelsi, P. Urquijo, Belle 2 -note-ph-2015 -002 Belle 2: improved KS reconstr. ; improved hadr. B tagging; LHCb: s s; run 2 50% less eff. for hadronic triggers than run 1; run 3 increase eff. for hadr. triggers by 2 x w. r. t. run 1; LHCb EPJC 73, 2373 Obergurgl, April 2017 B. Golob, Belle II 13/19
Introduction Plans Emiss Inclusive Neutrals Summary Plans BEPC-II / BES-III planning part of existing data sets: data y(3770) y(4040) 4. 18 Ge. V lumin. [fb-1] 2. 9 0. 5 3. 1 year 2010/11 2016 proposal until 2020 (3 years): 1010 J/y 3 fb-1 4. 6 -4. 65 Ge. V (Lc) 5 fb-1 4. 25 -4. 6 Ge. V (XYZ) Obergurgl, April 2017 B. Golob, Belle II 14/19
Introduction Inclusive Neutrals Summary Emiss Subjects Methods and processes where Belle 2 can provide important insight into NP complementary to other experiments: Emiss: B(B→ tn), B(B → Xctn), B(B → hnn), B(B → Xu l n). . . (Semi)Inclusive: B(B → sg), ACP(B → sg), B(B → sll ), . . . Neutrals: S(B → KSp 0 g), S(B → h’ KS), S(B → KSKSKS), B(t → mg), B(Bs → gg), . . . Detailed description of physics program at Belle 2 in: A. G. Akeroyd et al. , ar. Xiv: 1002. 5012 B. G. , , K, Trabelsi, P. Urquijo, BE LLE 2 -NOTE- PH-2015 -002 Impact of Belle II on Flavor Physics B. O’Leary et al. , ar. Xiv: 1008. 1541 P. Urquijo, BE LLE 2 -NOTE- PH-2015 -002 Physics of B Factories Belle I I - LHCb measurement extrapolation comparisons Ed. A. J. Bevan, B. Golob, Th. Mannel, S. Prell, and B. D. Yabsley, Eur. Phys. J. C 74 (2014) 3026 Obergurgl, April 2017 B. Golob, Belle II 15/19
Introduction Inclusive Neutrals Summary Emiss Missing energy B D*tn Belle, PRD 94, 072007, 700 fb-1 R(D(*))= B(B D*tn) / B(B D* R(D)SM=0. 300 ± 0. 008 l n) l =e, m Test of LFU H. Na et al. , Phys. Rev. D 92, 054410 (2015) R(D*)SM =0. 252 ± 0. 003 231 23 D* tn S. Fajfer et al. , Phys. Rev. D 85(2012) 094025 use NN with M 2 miss, Evis, cosq. B-D* l sig. data sample with low M 2 miss used to fit the background contribution 2800 57 D* l n signal is to the right → Obergurgl, April 2017 NN output for data with M 2 miss > 0. 85 Ge. V 2 B. Golob, Belle II 16/19
Introduction Inclusive Neutrals Summary Emiss Missing energy B D*tn R(D*)=0. 302± 0. 030± 0. 011 Belle, PRD 94, 072007, 700 fb-1 current Belle II 5 ab-11 Belle II 50 abs(R(D(*)))/R(D(*))[%] 3. 5 s @ 5 ab-1 5 s @ 20 ab-1 Nm/Ne (Brm/Bre)2 Nm/Ne Brm/Bre sstat(e/m) 5% sstat(t/e, m) 11% (semil. tag) semil. tag had. tag L [ab-1] Obergurgl, April 2017 B. Golob, Belle II 17/19
Introduction Inclusive Neutrals Summary Emiss CPV in b Neutrals → sqq some uncertainties cancel in DS (vtx reconstr. , flavor tag, likelihood fit) ; better KS eff. with vtx hits - larger vtx radius, 30%); vtx reconstr. improved with better tracking; B → J/y Ks for comparison 0. 007 41 new phases in MSSM DS=sin 2 f 1 eff -sin 2 f 1 B → Ks Ks Ks B → f Ks 0. 045 B → f Ks B → h‘ Ks 0. 020 0. 010 P. Urquijo, Belle 2 -note-ph-2015 -004 0. 02 Obergurgl, April 2017 B. Golob, K. Trabelsi, P. Urquijo, Belle 2 -note-ph-2015 -002 B. Golob, Belle II 18/19
Introduction Inclusive Neutrals Summary Emiss Neutrals Exotic states g ISR Belle II / BES III X(3872) discovery by Belle (2003) (meson molecule? ) clear that exotic ( ≠ qq, qqq) states exist PQ discovery by LHCb (2015) Belle II & BES III can produce those clearly and abundantly e+ Y e- Zc+(3900) e. g. Y states in e+e(quark gluon hybrids? ) Y(4260); BESIII 0. 8 fb-1 at Ecms=4. 26 Ge. V → J/y p+pstudies of properties (combined with LQCD? ) may reveal nature of exotic states BESIII, PRL 110, 252001 (2013) M. Padmanath et al. , PRD 92, 034501 (2015) Obergurgl, April 2017 B. Golob, Belle II 19/19
Introduction Inclusive Neutrals Summary Emiss Summary • complementarity is an absolute must in intensity frontier • need to do some (re)analysis of Belle data • hardly waiting to start datataking with Belle II B. Golob, K. Trabelsi, P. Urquijo, Belle 2 -note-ph-2015 -002 Obergurgl, April 2017 20. . 20 23 18 27? B. Golob, Belle II 20/19
Introduction Inclusive Neutrals Summary Emiss Beast phase 1 background drop Beast phase 1 backgrounds in ECL responding to colimator settings colimator closing Touschek background ( 1/sy) reason for lower boost Obergurgl, April 2017 B. Golob, Belle II 21/19
Introduction Inclusive Neutrals Summary Emiss B tn, hnn, Xctn, . . . possible to reconstruct events with n‘s; fully (partially) reconstruct Btag; reconstruct h± from Bsig; no additional energy in EM calorim. ; signal at EECL~0; Semil. tagging Missing E (n ) Btag Bsig → tn candidate event Partial reconstruction (semileptonic tagging): D*± l± etag~1% Bsig Btag n Obergurgl, April 2017 B. Golob, Belle II 22/19
Introduction Inclusive Neutrals Summary Emiss LFU/B →K* l l B K*l l Belle, ar. Xiv: 1604. 04042, 700 fb-1 R(K*)= N(B K*mm) N(B K*ee) approximate stat. uncertainty on R(K*), very roughly Belle, 0. 7 ab-1 Belle II, 10 ab-1 Obergurgl, April 2017 B. Golob, Belle II 23/19
Introduction Inclusive Neutrals Summary Emiss LFU charm s(X)/X[%] Ds l n B. G. , , K, Trabelsi, P. Urquijo, BE LLE 2 -NOTE- PH-2015 -002 RDst/m Br(Ds → mn) RDst/m= Br(Ds → tn) / Br(Ds → mn) Br(Ds → tn) Belle, JHEP 09, 139 (2013), 900 fb-1 RDst/m=10. 73 ± 0. 69 ± 0. 55 (RDst/m)SM= 9. 762 ± 0. 031 L [ab-1] n. b. : s(R(D*))/R(D(*)) ~4% @20 ab-1 Obergurgl, April 2017 B. Golob, Belle II 24/19
Introduction Inclusive Neutrals Summary Emiss Inclusive B s(+d) g continuum experimental challenge: huge bkg; only g reconstructed in the signal side Bsig p 0 gg h gg b sg g Xs Btag l± 1. 26 Ge. V < E < 2. 20 Ge. V Belle, PRL 103, 241801, (2008), 605 fb -1 different method: hadronic tagging (= full reconstruction of Btag); reduction of system. uncertainty on the account of lower efficiency (ehad ~ 0. 5%); K : p Bsig Btag g Xs 5% p B. Golob, K. Trabelsi, P. Urquijo, , Belle 2 -note-ph-2015 -002 Obergurgl, April 2017 B. Golob, Belle II 25/19
Introduction Inclusive Neutrals Summary Emiss Inclusive b dg within SM: Br(B → dg) / Br(B → sg) =(3. 8 ± 0. 5) 10 -2 (ratio can be used to determine |Vtd/Vts|) Br(B → sg) = 3. 4 10 -4 Br(B → dg) should be measured with an accuracy of sum of exclusive modes: Ba. Bar, PRD 82, 051101 (2010), 0. 4 ab-1 T. Hurth et al. , Nucl. Phys. B 704, 56 (2005) ~2 10 -6 s(Br(dg)) = (± 3± 1) 10 -7 low Xd mass region s(Br(dg)) = (± 20± 22) 10 -7 high Xd mass region largest syst. uncertainty: B → s g bkg. ; missing (>= 5 body) modes; significant improvement necessary Belle/Belle 2 full simulation: Belle 2 15% B 0 K*(Kp)g, B 0 r(pp)g, DE= EB* - Ebeam Obergurgl, April 2017 B. Golob, Belle II 26/19
Introduction Inclusive Neutrals Summary Emiss B → sg direct CPV Inclusive Ba. Bar, PRL 101, 171804(2008), 350 fb-1 Semi-inclusive, sum of many exclusive states: all flavor specific final states; b → sg <D>: average dilution due to flavour mistag, 1 DD: difference between flavour mistag for b and b, << 1 Adet: detector induced asymmetry HFAG, 2014 SM: ACP ~ (0. 44± 0. 240. 14)% Adet: careful study of K/p asymmetries in (p, qlab) using D decays or inclusive tracks from fragmentation; lots of work on system. , few 10 -3 exp. sensitivity T. Hurth et al. , Nucl. Phys. B 704, 56 (2005) 5 x 10 -3 Obergurgl, April 2017 B. Golob, Belle II 27/19
Introduction Inclusive Neutrals Summary Emiss DCPV puzzle: tree+penguin processes, B+(0)→K+p 0(-) DAKp= A(K+p -)- A(K+p 0)= -0. 147± 0. 028 Neutrals B 0 →K+p- Belle, Nature 452, 332 (2008), 480 fb -1 IKp B (B 0 → K+p -) Mbc M. Gronau, PLB 627, 82 (2005); D. Atwood, A. Soni, PRD 58, 036005 (1998) s(ACP(KSp+)) Belle 2 K 0 p 0 50 ab-1 s(ACP(K-p+)) B. Golob, K. Trabelsi, P. Urquijo, , Belle 2 -note-ph-2015 -002 Obergurgl, April 2017 B. Golob, Belle II 28/19
Introduction Inclusive Neutrals Summary Emiss Summary (Belle perspective) B. Golob, K. Trabelsi, P. Urquijo, Belle 2 -note-ph-2015 -002 Obergurgl, April 2017 B. Golob, Belle II 29/19
Introduction Inclusive Neutrals Summary Emiss Introduction Lumi ratio for same sensitivity B → f. Ks B → J/y. Ks P. Urquijo, Belle 2 -note-ph-2015 -004 B → tn Belle 2 Ee+beam Ee-beam from U(4 S) mass B. Golob, K. Trabelsi, P. Urquijo, Belle 2 -note-ph-2015 -002 Belle 2: improved KS reconstr. ; improved hadr. B tagging; LHCb: s s; run 2 50% less eff. for hadronic triggers than run 1; run 3 increase eff. for hadr. triggers by 2 x w. r. t. run 1; Belle II B-tagged LHCb Hadronic Relative yield increase LHCb EPJC 73, 2373 Obergurgl, April 2017 B. Golob, Belle II 30/19
Introduction Inclusive Neutrals Summary Emiss Early running - need time for calibration of detectors at U(4 S); measurements not requiring sophisticated PID and/or vertex determination; maximize impact on existing data samples (e. g. U(3 S)); A. Bondar et al. , Belle 2 -note-ph-2015 -003 Dark matter e+e- g A‘ g cc (mc < m. A‘/2) single g trigger required; simplified: single g, Eg > Ecut; high bkg, high trigger rate low e e: g. A‘ coupling Ecut main backgrounds: e+e- g e+ee+e- gg Obergurgl, April 2017 B. Golob, Belle II 31/19
Introduction Inclusive Neutrals Summary Emiss B tn, hnn, . . . Missing energy Nsig=62 ± 24 • fully (hadron tag) or partially (semil. tag) reconstruct Btag; hadronic tag B tn B(B+ →t+n)=(0. 72 ± 0. 26 ± 0. 11) ∙ 10 -4 Belle, PRL 110, 131801 (2013), 700 fb-1 Nsig=222 ± 50 B(B+ →t+n)=(1. 25 ± 0. 28 ± 0. 27) ∙ 10 -4 Belle, ar. Xiv: 1503. 05613, 700 fb-1 main syst. is reducible: bkg. ECL shape, e Btag) semil. tag Obergurgl, April 2017 B. Golob, Belle II 32/19
Introduction Inclusive Neutrals Summary Emiss B+ tn projected accuracy on B(B+ Missing energy →t+n) corresponding |Vub| uncertainty (experimental): semil. tag, 50 ab-1: 4. 5% hadr. tag, 50 ab-1: 3. 5% B. Golob, K. Trabelsi, P. Urquijo, , Belle 2 -note-ph-2015 -002 B →K(*)nn 5 x 10 -6 Br‘s expected to be „measured“ to 30% approx. expected precision @ 50 ab-1 SM W. Altmannshofer et al. , ar. Xiv: 0902. 0160 Obergurgl, April 2017 B. Golob, Belle II 33/19
Introduction Inclusive Neutrals Summary Emiss Super. KEKB ~10 mm, syy~60 nm ssxx~100 mm, s ~2 mm Nano beams design (P. Raimondi) ee+ b*: beta-function (trajectories envelope) at IP xy: beam-beam parameter ∫L dt [ab-1] ∫L dt=50 ab-1 (2022 -2023) small by* large xy (by*/ey) small ey hourglass effect small bx* increase I L [s-1 cm-2] ∫L dt=10 ab-1 (2018 -2019) current B factories design L=8· 1035 s-1 cm-2 magnet installation for Super. KEKB; Being built on schedule Obergurgl, April 2017 B. Golob, Belle II 34/19
Introduction Inclusive Neutrals Summary Emiss Introduction Super. KEKB Belle II e+ New IR New superconducting /permanent final focusing quads near the IP New beam pipe & bellows Replace short dipoles with longer ones (LER) e. Add / modify RF systems for higher beam current Redesign the lattices of HER & LER to squeeze the emittance Low emittance positrons to inject Positron source Damping ring Low emittance gun Low emittance electrons to inject New positron target / capture section Ti. N-coated beam pipe with antechambers Obergurgl, April 2017 B. Golob, Belle II 35/19
Introduction Inclusive Neutrals Summary Emiss Introduction Installation of 100 new long LER bending magnets done Installation of HER wiggler chambers in Oho straight section is done. Damping ring tunnel: built! Obergurgl, April 2017 B. Golob, Belle II 36/19
Introduction sin 2 f 1 Emiss Inclusive Neutrals General requirements Accelerator BF, KEKB @ KEK / PEPII @ SLAC U(4 S) b b Bd 0, B + b u, d Bd 0, B - b u, d s(e+e-→hadrons) [nb] Belle Ldt 1020 fb-1 Ba. Bar Ldt 550 fb-1 energ. threshold for BB production “on resonance” production e+e- → U(4 S) → Bd 0, B+Bs(e+e- → BB) 1. 1 nb (~109 BB pairs Belle) ”continuum” production, qq, ll, tt s(e+e- → c c) 1. 3 nb (~1. 3 x 109 Xc Yc pairs Belle) running at Y(n. S), e. g. Y(5 S) (Bs. Bs) Obergurgl, April 2017 ee+ g* (hadrons) f f B. Golob, Belle II (hadrons) 37/19
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