Status of NA 62 experiment Mauro Raggi 45

Status of NA 62 experiment Mauro Raggi, 45 th meeting of the LNF scientific committee Frascati, Nov 20 th 2012

The NA 62 collaboration @ CERN Sp. S Goal: BR(K+ → π+νν) to 10% 100 signal events S/B ~ 10 Jura mountains 13 + France 10 K decays with: Sp. S NA 62 North Area Acceptance ~10% Background rejection ~1012 Background known to ~10% LHC Time schedule Switzerland Geneva airport 07 -08: measurement of: RK = Ke 2/Kμ 2 with NA 48 07 -13: design, construction, installation Nov. 2012: Technical run from 2014: Measurement of ~100 K+ → π+νν decays NA 62 collaboration: Birmingham, Bristol, CERN, Dubna, Fairfax, Ferrara, Florence, Frascati, Glasgow, IHEP Protvino, INR Moscow, Liverpool, Louvain-la-Neuve, Mainz, Merced, Naples, Perugia, Pisa, Rome. II, Saclay, San Luis Potosí, SLAC, Sofia, TRIUMF, Turin M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 2

Searching for NP a different approach Intensity frontier A rare decay Indirect investigation on new physics is useful as a New Physics probe if: Search new degrees of freedom as alteration of SM rates. Explore symmetry properties of new d. o. f Λ ~ 1 -1000 Te. V 1) Process is (strongly) suppressed in the SM 2) Parameter to be measured precisely known in SM 3) There are specific predictions for NP contributions Example I LFV: RK=Ke 2/Km 2 Example II FCNC: K+�p+nn 1) Ke 2 process is helicity suppressed 2) RK known theoretically to 1/104 3) Deviation predicted by LFV 2 HD models (~1%) 1) pnn process is GIM suppressed 2) BR(pnn) known theoretically ~10% 3) Many prediction by different NP models Masiero, Paradisi, Petronzio, Phys. Rev. D 74 (2006) 011701 Straub CKM ’ 10 O(1%) on RK for Δ 13~5・ 10− 4 tan β~40 MH+~500 Ge. V NA 62 RK=(2. 488 ± 0. 007 stat ± 0. 007 syst) 10– 5 D(BR)/BR=0. 4% PLB 698 2011 105 -114 M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 3

The Cabbibo Kobayshi Maskawa matrix qu W+ V is unitary: V†V = 1 Vqq′ B unitarity triangle q′d Observable M. Raggi K unitarity triangle Measurement 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 4

K→πνν in the Standard Model Z-penguins s s d W t t Z Box diagram t W W n s d W n Z n n Loop functions favor top contribution d t W l n n QCD corrections for charm diagrams contribute to uncertainty CP s W d c c Hadronic matrix element obtained from BR(Ke 3) via isospin rotation M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 Z n n 5

Present status π +π 0 Measurement from BNL 787/949 Signal MC 7 candidate K+ → π+νν events BR = (1. 73+1. 15− 1. 05) × 10− 10 2× BRSM but entirely consistent J. Brod, M. Gorbahn, and E. Stamou Phys. Rev. D 83, 034030 (2011) M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 6

NA 62 experiment

The measurement technique An experimental nightmare Very small branching ratio Weak experimental signature • ~ 7 x 10 -11 • Only a pion in the final state • Cannot reconstruct K mass Huge Backgrounds • 61% K+�m+n decay • 21% K+�p+p 0( ) decay • 5% K+�p+p+p- decay Need rejection factors for BG up to 1012 to get S/BG>10 Kinematical Rejection Particle ID • K+4 -mom (Giga. Tracker) • p+ 4 -mom (Straw+MNP 33) BG rejection needed ~ 104 Vetoes extra particles • Positively identify p+ (RICH) • Veto photons from p 0 decays • Reject m, e (RICH+MUV) • Veto m from beam halo and K decays • Required up to 35 Ge. V • Need to cover huge range of energies • Need to cover all angles <50 mrad BG rejection needed ~ 103 BG rejection needed ~ 104 g ~ 105 m RICH ring radius p = 15 Ge. V e RICH ring radius p = 35 Ge. V π “μ” e “μ” π M. Raggi Mmiss 2 Rring [m] [Ge. V 2] 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 8

The NA 62 detector p+ K+ Tot length 270 m Primary protons: Beam: Total # kaons: K+ momentum: Measures: M. Raggi 3× 1012 protons/pulse from Sp. S with momentum of 400 Ge. V 750 MHz unseparated beam: 525 MHz π+, 170 MHz p, 45 MHz K+ 10% of K+ decay in FV ⇒ 4. 5× 1012 K+ decays/yr (75± 1) Ge. V Tag K, K and p momentum and time, p tag, veto all extra particle 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 9

The photon veto system 4 different detectors: LAV, LKr calorimeter, Intermediate ring calorimeter (IRC) and small angle calorimeter (SAC) Large Angle Photon veto (LAV) p+ RICH Vacuum decay tube < 10 -6 mbar 5 Ge. V 2 Ge. V ≈ 10 -5 g detection inefficiency q in 0 -8. 5 mrad acceptance M. Raggi 1 Ge. V (IRC) LKr (SAC) calorimeter 0. 1 Ge. V ≈ 10 -4 inefficiency Eg > 200 Me. V q in 8. 5 -50 mrad acceptance 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 10

LNF NA 62 group A. Antonelli, F. Gonnella, V. Kozhuharov, G. Mannocchi, M. Martini, M. Moulson, M. Raggi, T. Spadaro LNF SPAS: C. Capoccia, A. Cecchetti, E. Capitolo Group technicians: R. Lenci, V. Russo, M. Santoni, S. Valeri, T. Vassilieva LNF SELF: G. Corradi, C. Paglia, D. Tagnani LNF vacuum service: P. Chimenti, V. Lollo LNF mechanics workshop: G. Bisogni LNF metrology: M. Paris M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 11

LNF responsibilities on LAV detector The LNF group responsibilities in the LAV detector Coordination of the photon Veto System Design of the LAV vessel & construction equipment Test and calibration of the Pb. Gl blocks Assembly of the LAV stations Vacuum, HV and electronics tests LAV installation on ECN 3 cavern The LNF group responsibilities in the LAV readout Design and testing of new HV dividers for the R 2238 PMTs Project and development of FEE prototypes Production, validation and testing of the final FEE board Installation and commissioning of the whole LAV readout in ECN 3 Firmware for the L 0 LAV trigger primitive generation The LNF group responsibilities in software and MC Leading role in the LAV MC reconstruction Leading role in the development of new analysis tools M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 12

The LAV detector (synergy w NA, Rm 1, PI) LAV numbers • • • R 2238 76 -mm PMTμ-metal case 12 stations 4 -5 rings/layer 32 -64 blocks/layer ~ 2500 blocks total Operation in vacuum All particles from axis cross min 3 blocks (20 X 0) Lead-glass blocks from OPAL EM barrel Schott SF 57 lead glass 11 rings installed in vacuum tank +1 ring in air before LKr A 1–A 5 ∅2 m M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 A 6–A 8 ∅ 2. 5 m A 9–A 11 ∅3 m 13

LAV construction @ LNF “Banana” assembly Water damage New block wrapping M. Raggi Bond reinforced Banana installation 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 Completed 9 LAV now at CERN! 14

LAV in the ECN 3 cavern We already built at LNF 9 out of the 12 LAV stations 8 them are already been installed inside the cavern and the vacuum tank The decay region has been already evacuated to the pressure of ~10 -5 mbar 3 LAV are currently in use the technical run fully equipped with readout M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 15

NA 62 LAV readout chain LAV station FE board Readout TEL 62 PC Farm L 0 TP The LAV readout in numbers 2496 analog channels in 12 stations 4992 digital output to TEL 62 100 FEE boards + 12 TEL 62 boards ~ 100 KHz max rate per channel Requirements ü Time resolution <1 ns, ü energy resolution <10% at 1 Ge. V (using Time over Thr To. T) M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 16

LAV front end working principle to analog sum Amp 3 x Low Thresh. Split LVDS Compare Clamp FEE TDC + TEL 62 M. Raggi High thresh. LVDS Split the input signal in two: 1 copy to comparator + 1 to analog sums; Clamp the signal preserving its width; Lead Trail Threshold Amplify the signal x 3 to restore the overdrive; Compare signal with 2 independent thresholds clamp Produce an LVDS signal and send the signal to the digital read out board TEL 62; LVDS Measure the leading and trailing times of the TLead TTrail signal and compute the To. T=Trail-Lead; Use a parameterization to compute Q(To. T) To. T=TTrail. T 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 17

A 2 test beam CERN-PS, Aug/Sep 2010 σE/E T 9 beam: mixed e±, μ±/π±, p, 0. 3 -10 Ge. V Energy resolution σE/E = 8. 6%/√E ⊕ 13%/E σE/E = 9. 2%/√E ⊕ 5%/E ⊕ 2. 5% Energy resolution QDC Ee [Ge. V] M. Raggi To. T 4 m. V thr 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 Ee [Ge. V] 18

16 ch IN Analog 32 ch OUT LVDS To. T mezzanine card (16 x) 2 channels and 2 threshold per board. Threshold range 5 -250 m. V Includes the circuits for: Clamp, Amplifier, Comparator & LVDS driver. M. Raggi VME custom power 16 ch IN Analog Test pulse controller (1 x) Pulse height (set/read) Pulse width (set/read) Pulse rate (set/read) 32 ch OUT LVDS Board controller (1 x) Communicate using CAN-Open Allows setting and reading: Thresholds (set/read) Power connection (read) CANopen IN OUT The LAV Front End Board (LNF) Sum mezzanine card (10 x) Sum 4 analog channels (8 x) Sum 16 analog channels (2 x) Connected to a 50 W LEMO out 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 19

LAV Front end automatic test stand (LNF) Hardware layout x 2 RS 232 thr programming x 16 Pulser x 16 TDC CAEN 32 ch V 1190 B 32 ch LAV FEE Board VME Bridge V 1718 Linux PC GPIB programming Software flow chart repeat n times Program pulser repeat n times Run Daq binary raw to. root Entries Efficiency Data analysis DB Threshold profile Time resolution of 26 boards Threshold offset Avg(Tres)=85 ps Pulse amp(m. V) M. Raggi . root storage Entries Set FEE Threshold Pulse amp(m. V) 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 s. To. T ns 20

The LAV trigger primitive generator Corrects single hits for time slewing and detector offset Collect hits pertaining to the same particle Produce average hits time and compute event time Sort event times and send the list to L 0 TP Offset RAM 64 blocks (128 FIFOs) Data formatter & threshold retriever Slewing calculator to SL TDC FIFO Input Stage FIFO L FIFO H RAM PP 1 FIFO PP 2 FIFO Clustering unit Average calculator Sorting unit sorting RAM PP 3 FIFO M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 MTP generator Eth to L 0 TP PP 0 FIFO 21

2012 technical run achievements (so far…) Integration of 3 LAV station into the NA 62: Cabling of the detector completed Detector Control System remote control Full test of readout chain Development of analysis tool Standalone monitoring and analysis programs Integration with official data reconstruction Online monitor Analysis of first data from detectors Noise levels under control in all stations Time alignment with detector clocks OK Physics run with “ p+p 0” trigger done during Sunday night (some 106 events on disks) M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 22

Conclusions The LNF group has played a leading role in all aspects of the construction and installation of the LAV of the NA 62 experiment: Detector design, testing, assembly and installation Electronic design, production and testing Leading role in the software development Our group now heavily involved in the present technical run. We would like to thank: M. Raggi LNF SPAS: C. Capoccia, A. Cecchetti, E. Capitolo Group technicians: R. Lenci, V. Russo, M. Santoni, S. Valeri, T. Vassilieva LNF SELF: G. Corradi, C. Paglia, D. Tagnani LNF vacuum service: P. Chimenti, V. Lollo LNF mechanics workshop: G. Bisogni 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 23

Backup slides

Theoretical expectation for BR J. Brod, M. Gorbahn, and E. Stamou Phys. Rev. D 83, 034030 (2011) full two-loop electroweak corrections to the top-quark contribution Xt 10% Parametric error dominated by CKM 6% 8% 3. 7% Theory dominated by charm 1% 4% 3% sin 2 q W a 7% s 3% Xt(EW) k+ Mt Pc d. Pc, u 20% Mc 46% Vcb 57% 21% Xt(QCD) 24% The combination of tiny BR and high precision theoretical prediction allows to spot even for small deviations from SM induced by new physics degrees of freedom M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 25

What we can learn from K→pnn CKM constraints from: BR(K+ → π+νν) to ± 10% BR(KL → π0νν) to ± 15% εK to resolve ambiguities Im New physics models Ocariz, EPS ’ 09 a g b SM 4: SM with 4 th generation (Buras et al. ’ 10) RSc: Custodial Randall-Sundrup (Blanke ’ 09) LHT: Littlest Higgs with T parity (Blanke ’ 10) MFV: Minimal flavor violation (Hurth et al. ’ 09) M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 Re 26

What’s next: KL→p 0 nn Potential for future running with KL beam? KL → π0ℓ+ℓ− BRs could potentially be measured without significant upgrades FCNC decays with CP-violating components Useful in constraining the unitarity triangle KL → π0 vv need important intervention on photon vetos We are starting investigation on possible LAV upgrades M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 27

Sensitivity to LFV modes in NA 62 * Lower acceptances for electrons include effect of trigger energy threshold Only geometrical/trigger efficiency, various assumptions & simplifications: • Nominal kaon flux: ΦK = 5. 9 × 1012/yr for 105 m < z < 180 m • Flat phase space distributions • 2 years of data taking Trigger rates compatible • No backgrounds with main physics program M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 28

NA 62 RK RK 105 M 2 miss, all samples 145, 958 Ke 2 BG=(10. 95± 0. 27)% RK vs. pℓ bin Averaged over samples 0. 4% precision M 2 miss [Ge. V 2] pℓ [Ge. V] RK= (2. 488 ± 0. 007 stat ± 0. 007 syst) 10– 5 = (2. 488 ± 0. 010) 10– 5 Updates previous NA 62 result (40% data set) RK = (2. 487 ± 0. 013) × 10– 5 PLB 698 (2011) 105 M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 29

RK world average RK SM Average RK 105 RK/RK PDG 2008 2. 447 0. 109 4. 5% Current 2. 488 0. 009 0. 4% M. Raggi τν B→ Kμ /K 2 ℓ 3 New average Direct searches at LEP PDG 2008 tan β Tevatron Run II b s excluded Excl. by RK (95% CL) Δ 31 R = 10 × 10− 4 Δ 31 R = 5 × 10− 4 Δ 31 R = 1 × 10− 4 m. H+ [Te. V] MSSM with R parity 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 30

Cost review Core funding assigned by INFN to the NA 62 experiment M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 31

QQDC [p. C] Charge reconstruction in LAV TOT [ns] Measure To. T vs. charge using QDC and TDC only during calibration not during experiment Fit the function Q(To. T) (i. e. polynomial function) During data taking, measure the time using a TDC only M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 32

Simulations INPUT to simulation from GEANT 4 Number of photons in the event Arrival time of each photon Integrated charge (p. C) Photon wavelength Time over threshold (ns) M. Raggi 45 th meeting of the LNF scientific commettee Frascati 20 -21 Nov. 2012 33