C. Bloise LNF-INFN. The KLOE-2 project. XCVI Congresso Nazionale Società Italiana di Fisica settembre 2010

Transcription

1 C. Bloise LNF-INFN The KLOE-2 project XCVI Congresso Nazionale Società Italiana di Fisica settembre 2010

2 Outline Status Report on KLOE/2 at DAφNE Highlights on the KLOE-2 program Vus QM interference Low-energy QCD hadronic cross section γγ physics Conclusions C. Bloise - SIF - September 23,

3 KLOE data taking Integrated luminosity: 2005: 1256 pb : 734 pb : 320 pb : 172 pb -1 A total of 2.5 fb -1 of integrated luminosity at the φ peak About 250 pb -1 collected at 1 GeV for physics in the continuum C. Bloise - SIF - September 23,

4 DAφNE Upgrade A new collision scheme worked out with - large crossing angle - reduced beam size at the crossing point - sextupole pairs for crab-waist configuration of beam interaction A factor of 3 in the peak luminosity achieved with the same circulating currents C. Bloise - SIF - September 23,

5 Works at DAφNE for the run with KLOE-2 C. Milardi, EuCARD 1 st ANNUAL MEETING, April 2010 RAL, Oxfordshire-UK Performance still limited in November 2009 by: maximum positron current beam lifetime hardware reliability DAΦNE upgrade SIDDHARTA DAΦNE KLOE DAΦNE FINUDA L peak [cm -2 s -1 ] L day [pb -1 ] L 1 hour [pb-1 ] I - MAX I + MAX in collision [A] in collision [A] N bunches Status Report on DAFNE upgrade at EuCARD, April 2010 The first run of the upgraded DAφNE ended in November 2009 Interaction region revised for the operation with the KLOE magnetic field Several maintenance and upgrade works done to overcome the collider limitations clearing electrodes installed in the positron machines to prevent electron-cloud formation LINAC: new positron gun, new accelaring section (to be installed) Other elements modified: wiggler, kickers, control system, cryogenic plant, scrapers C. Bloise - SIF - September 23,

6 Project status and planning Works completed in July The machine commissioning just started Three-months period scheduled for major tuning of the operation Data taking planning as a function of the measured performance Upgrade of the KLOE detector by the end of 2011 C. Bloise - SIF - September 23,

7 The taggers for γγ physics Detector upgrade for the first KLOE-2 run : 2+2 detector stations for leptons in e + e - e + e - γ * γ * e + e - X LET (Low Energy Taggers) are LYSO calorimeters placed inside KLOE HET (High Energy Taggers) are scintillator hodoscopes placed 11 m from the IP C. Bloise - SIF - September 23,

8 Detector upgrades Major detector upgrades (late 2011) for the second KLOE-2 run: INNER TRACKER 4 layers of cylindrical triple GEM Better vertex reconstruction near IP Larger acceptance for low p t tracks QCALT W + scintillator tiles + SiPM/WLS QUADS instrumentation for K L decays CCAL LYSO + SiPM Increase acceptance for γ s from IP (21 10 ) C. Bloise - SIF - September 23,

9 Physics issues KLOE results mostly contributing to SM test in the flavor sector through precise measurements of Vus R K =Γ(K eν)/γ(k μν) CPT and quantum mechanics tests with the analysis of the QM interference of neutral kaons Ks semileptonic decays unitary (Bell-Steinberger) relation low-energy QCD the study of the light scalar sector precision measurement of the di-pion cross section for the calculation of the hadronic contribution to the muon anomaly C. Bloise - SIF - September 23,

10 The KLOE-2 physics program The program, in EPJ C68:619,2010, includes improvement on several KLOE measurements, γγ physics (multi)hadronic cross section Topics : CKM unitarity and lepton universality CPT symmetry and Quantum Mechanics Low-energy QCD Physics in the continuum: σ had Physics in the continuum: γ γ processes Hidden WIMP dark matter C. Bloise - SIF - September 23,

11 Cabibbo s hypothesis on lepto-quark universality CKM unitarity as stated in the SM implies the universality of the couplings of quark and leptons through the assumption G ij = Gμ V ij where j Vij 2 =1 Universality relations: G ij independent from lepton flavor Precision measurements of Vus constrain NP k π New physics encoded by shifts of both G μ and G semil G CKM = G μ ( V ud 2 + V us 2 + V ub 2 ) 1/2 = G μ ( 1 + Δ semil - Δ μ ) leading to a unitarity-violating term Δ CKM V ud 2 + V us 2 + V ub 2 = 1 + Δ CKM C. Bloise - SIF - September 23,

12 Testing Cabibbo s hypothesis KLOE performed a comprehensive, consistent set of measurements: -BR s, - lifetimes, - form factor dependence on Q 2 V us f + (0) = (5) from KLOE C. Bloise - SIF - September 23,

13 Vus/Vud from K μ2 decays VusisalsoobtainedfromK μ2 decays k As a result V ud 2 + V us 2 + V ub 2 = 1 has been verified at the level C. Bloise - SIF - September 23,

14 CKM unitarity and lepton universality From leptonic and semileptonic kaon decays Δ CKM = (6) a probe of the 10 TeV scale (v 2 /Λ 2 ) For comparison: Precision electroweak < Δ CKM < 10-4 From semileptonic kaon decays in muons and electrons separately: g μ2 /g e2 = r μe = 1.002(5) For comparison: (r μe ) π = (33) ; (r μe ) τ = 1.000(4) C. Bloise - SIF - September 23,

15 Improving on V us f + (0) KLOE-2 measurements : semileptonic BR s and lifetimes %err BR τ δ I Kl %err BR τ δ I Kl K L e (6) K L μ (7) K S e (13) K ± e (8) K ± μ (11) Aver (5) Recent big progress on LQCD calculation 0.1% level feasible C. Bloise - SIF - September 23,

16 CPT symmetry and QM The study of intereference with neutral kaon pairs at the φ-factory is a probe of CPT symmetry and QM at the Planck scale The sensitivity and a variety of interference phenomena for the unique, special circumstance ΔM ~ ½ Γ s With KLOE-2 we plan to improve on the vertex resolution with an inner tracker, realized with The GEM technology chosen for the super-light material Vertex resolution is expected to improve by a factor of 3 in the region of interest C. Bloise - SIF - September 23,

17 The triple-gem cylindrical chamber arxiv: C. Bloise - SIF - September 23,

18 From KLOE to KLOE-2 Decoherence (loss of total entanglement between kaons) can be traced back tomodifications in QM CPT violation at the Planck scale from Quantum Gravity Sensitivity limited by statistics Improvements in the vertex resolution from τ s equivalent to a factor of 3-4 in statistics C. Bloise - SIF - September 23,

19 Low-energy QCD Kaon and η decays in a clean environment The only experiment with Ks pure beams KLOE-2 can study kaon channels with BR s to 10-9 The interest is for Radiative and Dalitz decays Rare Ks decays; Ks 3 π, γγ, π 0 γγ, π 0 l + l, π + π γ, π + π e + e η decays: π 0 γγ, π + π e + e, eeee η decays: improvement of the BR s to 1% First observation of η e + e e + e Preliminary φ ηee, ημμ φ KsKs γ C. Bloise - SIF - September 23,

20 CCALT 2 small barrels of 24 crystals each with length cm and transversal area from 1.5x1.5cm2 to 2x2cm2 The angular acceptance is extended to 10 Dodecagonal Barrel w/o CCAL Ks γγ with CCAL 26/10/ cm Crystal cm C. Bloise - SIF - September 23,

21 Physics in the continuum: hadronic cross-section Hadronic cross section at low energy to obtain hadronic contributions to (g-2) μ α(m Z ) Di-pion cross section as a functions of s using ISR events and the radiator function H(s,s ) Independent measurements of ππγ cross section with small-angle photons large-angle photons and s = 1 GeV 2 for the uncertainty from scalar contributions with ππγ normalization to μμγ event C. Bloise - SIF - September 23,

22 KLOE results KLOE KLOE F π 2 KLOE09 KLOE F π 2 ( F π 2 KLOE08 - F π 2 KLOE09 ) / F π 2 KLOE09 KLOE08 M(M 2 ππ) 0 2 [GeV 2 ] (Mππ) 0 2 [GeV 2 ] F π 2 KLOE09 CMD SND M 2 ππ KLOE09 CMD SND The most recent result with photons at large angle are from s = 0.1 GeV 2 very near di-pion threshold Results consistent with the analysis of events with photons at small angle M 2 ππ (M 0 ππ) 2 [GeV 2 ] F π 2 ( F π 2 CMD,SND - F π 2 KLOE09 ) / F π 2 KLOE09 SND CMD-2 (Mππ) 0 M 2 [GeV 2 ] ππ C. Bloise - SIF - September 23,

23 The results on (g-2) μ KLOE analysis with the sample normalized to μμγ : ongoing Improvement by a factor of 2 in a μ HLO calls for both, improvements of the di-pion cross section near threshold, and the multi-hadronic cross sectio in the [1-2.5] GeV region KLOE-2 results with photons at large angle not included C. Bloise - SIF - September 23,

24 Data taking proposal with KLOE-2 The 0.7% uncertainty in σ had at s<1 GeV can be reduced to 0.4% with O(fb-1) off-peak integrated luminosity at DAFNE Reduction of the uncertainty on σ (1 < s< 2) GeV from 5% to 2% is also needed to have δa μ had,l0 δa μ had,lbl and δa μ SM Di-pion production threshold: Run at s 1 GeV 2 Direct scan above 1 GeV with DAφNE upgrade in energy C. Bloise - SIF - September 23,

25 Physics in the continuum: γγ physics Meson γγ widths Pseudoscalar FF and contribution to LbL Scalar study via ππ spectrum L int = 1 fb 1 C. Bloise - SIF - September 23,

26 Pseudoscalar ff and LbL γ γ P F(P 2,q 2,0) Tagged sample needed for background reduction Ongoing studies at KLOE on the off-peak sample shown by I. Prado Longhi in this session C. Bloise - SIF - September 23,

27 Conclusions KLOE hasbeenabletoaddressmanytopicsoffundamentalphysics with precision measurements in kaon physics, η/η decays, low-mass scalars, and hadronic cross section The physics program will continue at KLOE-2 which is ready for data taking at the upgraded DAφNE Machine commissioning underway A tagger system for γγ events has been installed The construction of the inner tracker for improving on vertex reconstruction at the IR and calorimeters to instrument the quadrupole region and to detect smallangle photons has been started to be ready for installation by end of 2011 C. Bloise - SIF - September 23,

28 Spares C. Bloise - SIF - September 23,

29 R μ23 New-physics could affect the helicity-suppressed kaon decays only R μ23 is used to constrain models with Higgs-mediated scalar currents R μ 23 = f f k + (0) / f π V V us ud f f k π μ 2 V tan β ( ) 2 V f (0) m + 1+ ε tan β us ud + l3 1 m 2 k H 0 2 R μ23 = ± C. Bloise - SIF - September 23,

30 LQCD calculations and expt slopes FlaviaNet Kaon WG ArXiv: publ. by EPJC From the dispersion parametrization of the ff dependence from the momentum transfer, based on analyticity constraints and CT theorem, the experimental measurement of the ratio f k /f π /f + (0) = 1.225(14) is obtained UKQCD/RBC F lavi A net Kaon WG KLOE ISTRA+ NA48 KTeV f + (0) C. Bloise - SIF - September 23,

31 First milestones at KLOE-2 The KLOE-2 analysis board worked out the milestone to focus the efforts of the collaboration γγ physics : measurement of the acceptance vs Q 2 φ η e + e : measurement of the form factor η η π + π : measurement of the M ππ distribution φ Ks Ks γ : improved upper limit, first evidence of the decay Exclusion plot for e + e Uγ l + l γ, e + e ηu η l + l e + e h γ X Miss l + l K S π 0 π 0 π 0 K S K S π 0 π 0 π + π Measurement of Im(ε /ε) C. Bloise - SIF - September 23,

32 C. Bloise - SIF - September 23,

33 σ had : normalization to μμγ The measurement does not depend from corrections for vacuum polarization and from the luminosity measurement C. Bloise - SIF - September 23,

34 Hadronic contribution to α em A reduction of the uncertainty on σ (1 < s< 2) GeV from 5% to 1% needed to have δα em /α em δg μ /G μ δm Z /M Z O(10-5 ) G.Isidori C. Bloise - SIF - September 23,

35 γγ η from KLOE data at 1 GeV Fit to p L and M miss2 with signal and background shapes ~ 600 signal events PRELIMINARY e + e - > ηγ > π + π π 0 γ 80χ 2 fit /d.o.f.= 75.9/83 100χ 2 fit /d.o.f.= 59.8/43 e + e - > e + e - γ signal p L (MeV) M miss (GeV 2 ) Extraction of σ(e + e e + e η) and Γ γγ in progress Statistical accuracy on Γ γγ comparable with existing measurements C. Bloise - SIF - September 23,

36 Hidden WIMP dark matter Light particles from a secluded sector proposed as DM candidates The search at KLOE with the study of the dilepton spectrum associated to photon and η production C. Bloise - SIF - September 23,

37 U-boson associated to η decays Reece and Wang arxiv: Ongoing analysis on KLOE data C. Bloise - SIF - September 23,