New Kaon projects Augusto Ceccucci / CERN Indirect Searches for New Physics at the time of LHC GGI March 24, 2010 Augusto Ceccucci 1
Experimental Techniques Search for New Physics Beyond the SM n n K + p + Rarity Frontier Energy Frontier • Look for deviations from precise SM • Produce heavy new particles directly predictions, CKM, K, D, B Decays, Leptons • Heavy particles need large colliders • Look for rare or forbidden processes • LHC Media Event: March 30, 2010! • Requires high precision & intensity GGI March 24, 2010 Augusto Ceccucci 2
“New” Kaon Project “at the time of the LHC” • There is some freedom in defining a “New Kaon ” project when the framework is defined as the “time of the LHC” • I take here a broad perspective considering projects that have been approved and in construction and also projects with a bit longer time-scale and an uncertainty. • I will refrain from mentioning kaon projects for the 2030+, although one could argue that the exploitation of the LHC may well extend into those years……. GGI March 24, 2010 Augusto Ceccucci 3
Motivation • Physics motivation in Isidori’s talk, in addition: • Interplay between technology and science – Development of beyond state-of-the-art detectors for eventual use at future collided and other applications (e.g. time-stamping) • Training ground for young experimentalists: – opportunities to educate the next generations of students giving them – if history is a guide – excellent opportunities GGI March 24, 2010 Augusto Ceccucci 4
Outline • CKM Unitarity (V us ) • Lepton Universality (R K ) • Ultra-Rare K decays ( K p nn ) • Kaon Interferometry ( KK) GGI March 24, 2010 Augusto Ceccucci 5
CKM Unitarity: V us • Experiment: Flavianet average of K 0 s /K 0 L / K semi-leptonic modes: f + (0) |V us |= 0.21664 +/- 0.00048 → 0. 22 % relative error! • Lattice QCD (RBC UKQCD): f + (0) = 0.9644 +/- 0.0049 →| V us | =0.2246 +/- 0.0012 • Wait for Chris Sachrajda’s talk for lattice QCD f + (0) determination GGI March 24, 2010 Augusto Ceccucci 6
R K : Lepton Universality Test with K + l + n SM New Physics <0.1 % precision of the SM prediction GGI March 24, 2010 Augusto Ceccucci 7
K e2 : 40% of data set K e2 candidates 51,089 K + e + n candidates, 10 4 99.2% electron ID efficiency, 10 3 Backgrounds: Source B/(S+B) (6.28 0.17)% K 2 10 2 K 2 ( e) (0.23 0.01)% K e2 (SD + ) (1.02 0.15)% 10 1 Beam halo (0.45 0.04)% K e3 0.03% K 2 p 0.03% Total (8.03 0.23)% 0.011 syst ) 10 – 5 R K = (2.500 0.012 stat 0.016) 10 – 5 R K = (2.500 Presented by Evgueni Goudzovski at KAON2009 Augusto Ceccucci 8 GGI March 24, 2010
Comparison to world data March 2009 June 2009 R K 10 5 World average Precision With the full NA62 data sample of 2007/08, the precision is expected to be improved to 2.467 0.024 March 2009 0.97% better than K R /R K =0.5%. 2.498 0.014 June 2009 0.56% GGI March 24, 2010 Augusto Ceccucci 9
R K : sensitivity to new physics (M H , tan ) 95% exclusion limits R K measurements are currently in agreement with the SM expectation at ~1.5 . 100 2HDM tan Any significant enhancement with respect to the SM value would be an evidence 80 of new physics. 60 For non-tiny values of the LFV slepton mixing 13 , 40 the sensitivity to H in R K =K e2 /K 2 is strong 20 “Maybe NA62 will find the first evidence 0 800 200 400 600 1000 for a charged Higgs exchange?” Charged Higgs mass [GeV/c 2 ] -- John Ellis (arXiv:0901.1120) GGI March 24, 2010 Augusto Ceccucci 10 E. Goudzovski / Moriond EW, 10 March 2010
Ultra-rare K Decays pn n K • The contribution to these processes due to the Standard Theory is strongly suppressed (<10 -10 ) and calculable with excellent precision (~%) • They are very sensitive to possible contributions from New Physics GGI March 24, 2010 11 Augusto Ceccucci
K p n n : Current Status 10 Decay Branching Ratio ( 10 ) Theory (SM) Experiment [ 2 ] + + + p n n [ 1 ] 1 15 . ( ) 0 85 0 07 1 73 K . . . 1 05 - . p n n 0 0 [ 3 ] [ 4 ] 0 26 0 . 04 260 ( 90 % CL ) K . L PRL101, arXiv:0808.2459 GGI March 24, 2010 Augusto Ceccucci 12
L p 0 nn Neutral Beams for K 0 “ Microbunched ” “Pencil” – E K from Time Of Flight – p 0 + “nothing” – Low(er) Kaon Energy – P T cut for L n p 0 & – KOPIO BNL Concept L 2 p 0 suppression K 0 further elaborated for FNAL – hermetic calorimetry (Bryman@KAON09) Exp Machine UL 90% CL Notes < 5.7 x 10 -7 ( p 0 ee ) KTeV Tevatron <2.6 x 10 -8 E391a KEK-PS KOTO J-PARC Aim at 2.7 SM evts / 3 y KLOD U70 Excellent Design KOPIO Opportunity at Project X (IC2) ? GGI March 24, 2010 Augusto Ceccucci 13
E391a @ KEK PS KEK 12GeV PS East Counter Hall A-line C-line E391a MC L → p 0 nn K 0 GGI March 24, 2010 Augusto Ceccucci 14
E391a Final Result • arXiv:0911.4789v1 Signal Acceptance ~1% • Based all full statistics (2004- Flux 8.7 x 10 9 K 0 L 2005) including reanalysis of already published data CV • At these sensitivities CC02 backgrounds from kaon decays are negligible w.r.t. neutron induced ones Background Estimated # evt CC02- p 0 Beam Halo 0.66 0.39 CV- p 0 neutron <0.39 CV- h 0.19 0.13 L → p 0 nn ) < 2.6 x 10 -8 90% CL B(K 0 L → p 0 p 0 K 0 (2.4 1.8) x 10 -2 Backward p 0 Other <0.05 Factor of x3 improvement Total 0.87 0.41 GGI March 24, 2010 Augusto Ceccucci 15
KOTO (E14) @ JPARC Aim for Flux x Run Time x Acceptance = 3000 x E391a Main Ring Parameters: L=1.6 Km 30 GeV Details in H. Nanjo 2 x 10 14 ppp KAON’09 0.3 MW 0.7 s spill / 3.3 s GGI March 24, 2010 Augusto Ceccucci 16
KOTO @ JPARC Use KTeV Xtals Schedule (H. Nanjo, KAON2009) Expectations: 2009 L p 0 nn • Beamline construction K 0 Signal 2.7 • Beam Survey p 0 p 0 K 0 1.7 L 2010 Background • CsI Calorimeter Construction p + p - p 0 0.08 • Engineering run with CsI calorimeter e + p - n 0.02 2011 • Physics Run start Halo Neutrons 0.38 GGI March 24, 2010 Augusto Ceccucci 17
“Confirmation of neutral kaons in the KL beam line at Hadron Hall, J- PARC” Dec 7, 2009 Beam Survey L → p + p - p 0 K 0 GGI March 24, 2010 Augusto Ceccucci 18
Plans for K 0 L @ FNAL Project X • KOPIO-like: TOF to determine Kaon Energy • Knowledge of E K allows rejection of two body decays • Project X (IC2): CW p LINAC ~3 GeV • Pointing Calorimeter • Excellent bunch timing • 4 p veto for neutral and charged particles • High flux of low energy K 0 • Small Beam instead of flat beam L GGI March 24, 2010 Augusto Ceccucci 19
Techniques for K + p + nn “In - Flight” “Stopped” – Decays in vacuum (no – Work in Kaon frame scattering, no interactions) – High Kaon purity – RF separated or (Electro-Magneto-static Unseparated beams Separators) – Extended decay regions – Compact Detectors Exp Machine Meas. or UL 90% CL Notes < 5.7 x 10 -5 Argonne Stopped; HL Bubble Chamber < 5.6 x 10 -7 Bevatron Stopped; Spark Chambers Stopped; p + + e + <1.4 x 10 -7 KEK (1.57 +1.75 -0.82 ) x 10 -10 E787 AGS Stopped (1.73 +1.15 -1.05 ) x 10 -10 E949 AGS Stopped; PPN1+PPN2 NA62 SPS In-Flight; Unseparated P996 FNAL Stopped; Tevatron as stretcher ring? 20 GGI March 24, 2010 Augusto Ceccucci
E787/E949: Final Result arXiv:0903.0030v1 PRD79:092004,2009 “PNN1” “PNN2” B( K + p + nn ) = (1.73 +1.15 -1.05 ) x 10 -10 GGI March 24, 2010 Augusto Ceccucci 21
E787/E949 Technique “The entire AGS beam of 65 x 10 12 (Tp/ spill) at a momentum of 21.5 GeV/c was delivered to the E949 K + production target” • Duty Factor: 2.2 s / 5.4 s ~ 40% • 1 int. length Pt target • Before separators: 500 p : 500 p : 1 K • After separators: Purity K: p ~ 3-4 : 1 • Incoming 710 MeV/c K + identified by Č and slowed down by BeO and Active Degrader • ~27% K + stopped in the target (1.6 MHz) • 1 T solenoid p + : Delayed Coincidence K + : Č x B4 x Target Range Energy Momentum p + + e + GGI March 24, 2010 Augusto Ceccucci 22
Stopped Kaon Redux? Can one improve significantly over the E949 PNN1 efficiency figures? a •“Only” ~22% (.77 x .28) of kaons stopped Selection Notes in target K 2 0.38 Beam,T, RS rec. K p 2 0.88 E, range, selection • The product of the red factors (1.5 x 10 -2 ) Pscat 0.62 Rej. of beam scat. Is a high price to pay: 1/(1.5 x 10 -2 ) ~ 66x p e 0.35 Decay chain Possible Improvements (Bryman@KAON09): Trig 0.18 Trigger eff. PS 0.36 Phase Space 1. Lower Kaon Momentum to nucl. 0.50 Pion interaction increase the stopped kaon fraction T2 0.94 topology 2. Larger Beam acceptance 4-5x fs 0.77 Stopping Fraction 3. Detector Improvement: finer “Standard” 1.7 x10 -3 Total efficiency RS segmentation; LXe veto > 5x GGI March 24, 2010 Augusto Ceccucci 23
Recommend
More recommend
