Status of Is the CKM matrix the only source of CP violation? Leo Bellantoni Fermilab Users' Meeting June 2002

where (Buchalla & Buras, Falk et. al., D'Ambrosio and Isidori) Hadronic effects well understood K +    K+K+ ++ Compare B -  D 0 e - : HQET vs data

K +    0.79  0.10 <0.032 (BNL) From fit by D'Ambrosio and Isidore, PL B530 (2002) 108 using above constraints, |V ub / V cb |,  K, and  m(B d )

K +    The CKM result in the event of no new physics

K +    In SUSY, branching ratio could be up to 210% (conceivably, much more) of the Standard Model value, leading to the above CKM result Buras,Colangelo,Isidori,Romanino,Silvestrini Nucl.Phys B566(2000)3.

K +    In MSSM, branching ratio could be between 65 to 102% the Standard Model value, leading to the above CKM result Buras,Gambino,Gorban,Jager,Silvestrini Nucl.Phys B592(2001)55.

K +    Buras et.al. found an "unlikely" SUSY scenario that gives enhancements of Br(K +    ) up to 3x the SM level Baek,Jang,Ko,Park, Nucl.Phys., B609(2001)442 also show a SUSY scenario where Br(K +    ) differs markedly from the SM level Hattori,Hasuike,Wakaizumi, Nucl.Phys., B592(2001)55 also found large branching ratio enhancements in their 4 generation model D'Ambrosio and Isidori, Phys.Lett., B530(2002)108 discusses the case where new physics has led us to draw the wrong constraint from B d mixing

BNL E787 reports 2 clean events With recent ( ,  values, expect BNL E949 (upgrade of E787) expects to see events using stopped K +  Run has started  Needs 2 more years worth of data  Joint collaboration with CKM (FNAL / BNL / IHEP) CKM plans to see 100 events using the Main Injector and decay in flight PRL 88, (2002) K +    at  3  level,

Other Physics Lepton flavor violation K +   +  + e - K +   +  - e + K +   -  + e + K +   -  +  + K +   - e + e + T violation in K +   0 l +  Search for pseudoscaler in K +  e + Direct CP violation in 3 ,  Form factors in K +   + l + l -

Detection Fiducial region limited by beam energy, background from K , use of RICH to measure  + velocity, need for K +  + vertex M 2 MISS = M 2 K (1 - p  /p K ) + m 2  (1 - p K /p  ) – p  p K  % x 1.6% x (8 x )  Need ~4 x K + !

Initial momentum-selected beam (  +, p, K + )  P/P ~ 2% RF deflection: Asin(  t) A ~ 15 MeV/c Transport L = (integer)   c /f  t then integer multiple of 2  for  + 2nd RF deflection e.g. 180 o out of phase: - Asin(  t+  t) For  +, no net deflection For K +, deflection is 2A sin(  n   /  K )  cos(wt+  n   /  K ) Stop  + with beam plug, collect K + X X 86.4 m 12.9 m RF separated K + beam

Turtle/GEANT simulation:  Debunched 22GeV beam (+2%)  33MHz of K + per 4 x ppp  71% Kaon purity  Total charged particle rate into detector <50MHz; muon component is 7.4MHz  Achieves baseline CKM requirements Need 5MeV/m P  kick for 1sec spill  need superconducting cavities to create the deflection RF separated K + beam

Expressed as B MAX on inner Nb surface: This result:104mT Our 5MeV/m: 77mT MeV/m:110mT MeV/m:160mT RF separated K + beam A recent 1-cell test result Q P  (MeV/m) Our Design Goal Thermal Breakdown Have similar results on 2 other small structures, but still need to improve (And have lots of tricks to try for that)

Detection What We Want: K+K+ ++ What We'll Get: K+K+ ++ Br = 63.5% Also K +  + K+K+ ++  0  (undetected) Br = 21.2% K+K+ ++ X (undetected) A Kinematics  + Veto  Veto Charged Veto Low Material Momentum, direction & position of K + and  +

Detection Redundant measurements essential

Tracking vs. RICHs

Straw Tubes Mechanical stress and leak rate testing 2 x atm-cc/sec-straw (N 2 ) Fe 55 source used to locate active region, wires Typically   0.002" from nominal Ru 106 source to measure drift times 20 straw prototypes testing in Lab 3

Photon Veto System Small prototypes studied 2 sector (0.3%) prototype being built now Tagged e - beam test at Jlab Sept/Oct 20 layers scintillator per PMT 4 PMTs per sector in VVS ~4200 PMTs in entire  veto system

We plan to explicitly test the factorization hypothesis in an early special / engineering run K +   0  + Veto Test We use the factorization to estimate the K +   0  + background; i.e., we multiply overall  0 veto inefficiency of 1.6 x by our kinematic rejection factor of 1/30000 BNL E787 has tested factorization by plotting P(  + ) line in K +   +  0 with (a) no  veto cuts, (b) online  veto cuts, (c) full analysis cuts

Electronics / DAQ 50MHz debunched beam  need continuous deadtimeless digitization TDC every (~30000) channel, QDC on ,  + vetos (~8000 channels) Recent history of detector activity is important Imagine 2 K +  +  0 events 10ns  PMT deadtime apart K+K+ K+K+ ++ ++    (Branching Ratio) 2 / (Number of  veto channels) 2 = 2 x >> 8 x Br we want to measure Studying triggerless DAQ (just say yes and trigger at level 3 in software) 

And at the end… M 2 MISS = M 2 K (1 - p  /p K ) + m 2  (1 - p K /p  ) – p  p K  2

Spares

Br(K +    ) =   + { [ I(V td V ts * ) X(M t /M W ) ] 2 CPV top loops +[ R(V td V ts * ) X(M t /M W ) CPC top loops +R(V cd V cs * ) P(M t,  s (  )) ] 2 } Charm contribution; P = 0.42  0.06  + =0.901 K +    3  2 Br(K +  0 e + ) 2  2 sin 4  W sin 2  C Known to +2.5% Charm contribution adds ~3% error in Br for any given I (V td V ts * ) With current V CKM values Br(K +    ) =(0.81  0.15)x (Hocker et.al., 2001) (Buchalla & Buras)

RF separated K + beam

Preliminary Specs 3.9 GHz, TM 110  mode  15mm iris radius  47mm equator radius  38mm cell length 26 cells per meter 5 MeV/m P  kick; 15 MeV/station E peak = 19MV/m B peak = 77mT Transverse shunt impedance 702  /m Q x R SURF is 228  Stored energy 0.73 J/m 8.5 W/m dissipated into LHe 1.8 ~ 2.0 K Q:2.2 x 10 9 (unloaded) 6.0 x 10 7 ( loaded )

Measuring the K + UMS - high rate PWCs  2 stations of 6 planes each  Rate ≲ 0.90 MHz/cm 2 – compare HyperCP rates of 0.75 MHz/cm 2 K + RICH - velocity spectrometer  10m long N 2 1.1atmospheres with ~10 detected photons  22GeV beam gives K + resolution in (  ) to +0.5%

Measuring the  +  20m long Ne 1atmosphere:  Straw Tube tracker: (total 13 layers)

K +,  + RICHs 22GeV beam gives K + resolution in (  ) to +0.5% K + RICH is 10m long CF 4 (or N 2 ) radiator with ~10 detected photons  + RICH is 20m long Ne radiator with 3000 PMTs Challenges include:  Need 0 2 contamination at O (10 -6 )  Low mass mirrors  High rate (~1MHz) photomultiplier tubes  Gaussian tails in resolution to 5 orders of magnitude Drawing heavily on the SELEX experience

SELEX RICH cm

Photon Veto System Design assumes the demonstrated performance of BNL-E787 system (1mm Pb / 5mm Scintillator) for vetoing low energy ( MeV) photons  angle and E(  ) correlated in K +  +  0  50% coverage E(  ) > 1GeV in VVS  +  0 events critical

Online monitoring is crucial ~ Two seconds of undetected dead time in two years of data taking blows the inefficiency budget Photon Veto System Small prototypes studied 2 sector (0.3%) prototype being built now Tagged e - beam test at Jlab Sept/Oct Events with an E(  ) > 1GeV in VVS have the  enter at ~30 mrad angle GEANT simulation says 3 x inefficiency can be achieved over 1GeV Photoproduction effects (e.g.,  Pb   K 0 ) in > 1GeV region: Total cross section ~4mBarn  4 x inefficiency – but most of those final states will be detected Engineering problems are formidable!

 + Veto Need to reject 14-20GeV  + from K +  2 decays at O (10 -5 ) level What could make a  + fake a  + ?  + bremsstrahlung  +  e + DIS Tested a 26 layer (41mm Fe) / (10mm scintillator) 0.6 x0.6 meter prototype in Nov 2000 at IHEP(Protvino) with ~19GeV momentum analyzed  + beam: 12 x 2 segmentation After cuts on shower shape,   acceptance (3~4) x10 -6, with   acceptance 75.3% Corresponding GEANT numbers are 2 x10 -6, 69%