1 PHYSICS IN THE NuMI BEAM with a ~10 kiloton LARTPC prototype ASH RIVER or SOUDAN J.Schneps PRELIMINARY,UNFINISHED, & ROUGH Sept. 27, 2007

2 If a ~10 kiloton LArTPC prototype is to be built it makes sense to place it in the NuMI beam at a location where it can contribute to   e oscillation physics. The two sites where infrastructure will exist short-term are Ash River (off-axis) near NOvA, and the Soudan site (on-axis), near MINOS and CDMS (probably on the surface but possibly underground).

3 ASH RIVER - This has already been studied. The LArTPC would approximately double the statistics of NOvA for a numu - nue appearance signal. The NC background would be negligible, but it is already reasonably small for NOvA. The main physics gain would be improving the attainable limit on sin 2 2  13 by  2. Another advantage, if sin 2 2  13 is large enough to be seen early in the neutrino run, would be to switch to antineutrino running sooner and run longer to get at CP violation.

4 SOUDAN - The main advantages on-axis in the ME wide-band beam are 1) a large increase in the signal and 2) looking at the physics with a different energy distribution and L from the NOvA off-axis beam. There is also the possibility of going underground to shield against cosmics. The disadvantages are the larger backgrounds from intrinsic nue and NC(pi0). Thus, the question of how well we can control the NC background at higher energies is crucial. Any detector other than a LArTPC is probably hopeless.

5   e Oscillations (Not including matter effects; - for nu, + for antinu)

6 NuMI ME Neutrino Beam Event Rates

7 Assume LArTPC ready for start of NOvA in ME Beam 30 X pot exposure to neutrinos NOvA: 15 kilotons and 40% efficiency for e LArTPC: 10 kilotons and 85% eff. for e

8 15 kiloton NO A; 30x10 20 pot;  =40%; L=810km sin 2 2  13 =0.10;  m 21 2 =8x10 -5 eV 2;  m 31 2 =2.5x10 -3 eV 2 E(GeV)  CC (100%) e CC (100%) EV 1 EV 2 EV 3 /sin  EV 4 /cos  e B nc Totals

9 NOvA For  =0, signal S= =143.4 background B= = 28.0 observed N=171.4 S=N-B, (  S) 2 =(  N) 2 +(  B) 2 =N+B=S+2B  S=(S+2B) 1/2 = 14.1 (  S/S)=(14.1/143.4)=0.098   (sin 2 2  13 )/ sin 2 2  13 or sin 2 2  13 =  (~10 s.d. from zero) LARTPC(Ash River) S=143.4x(2/3)x(.85/.40)= B=( )x(2/3)x(.85/.40)=29.7 (no NC) (  S/S)=(16.2/203.1)=0.080 sin 2 2  13 =  (~12.5 s.d. from zero) NOvA+ LARTPC ; sin 2 2  13 =  (16 s.d from zero)

10 3 S.D. Sensitivity Limiits for  =0 or NOvA B=28.0  S=27.4 corresponds to sin 2 2  13 = LArTPC B=29.7  S=28.1 corresponds to sin 2 2  13 = NOvA + LArTPC B=57.7  S=37.0 corresponds to sin 2 2  13 = We have omitted various systematic errors, e.g.,  E, uncertainties in e beam, NC background,etc., so results are optimistic but “in the ballpark”.

11 10kton LArTPC; L=735 km; ME Beam on-axis; 30x10 20 pot; eff.=100%; sin 2 2  13 =1.0;  m 21 2 = 8x10 -5 eV 2 ;  m 31 2 = 2.5x10 -3 eV 2 E(GeV)  CC e CC EV 1 EV 2 EV 3 /sin  EV 4 /cos 

12 E(GeV)  CC e CC EV 1 EV 2 EV 3 /sin  EV 4 /cos 

13 sin 2 2  13 =1.0 ;  =100% E(GeV)  CC e CC EV 1 EV 2 EV 3 /sin  EV 4 /cos  = TOTALS

14 10 kton LArTPC at Soudan;  = < E < 8.0 GeV sin 2 2  13 =0.10; sin2  13 =0.3162;  =0 S=6651.1x0.1x x x0.3162x0.85 = B=( )x0.85=293.3 (assumes no NCBG)  S=(S+2B) 1/2 = 35.4 ; (  S/S)=0.053 or sin 2 2  13 =  S.D. from zero limit corresponds to sin 2 2  13 = NOvA +LArTPC(Soudan) 3 S.D. limit, S=80.7, And sin 2 2  13 = BUT ASSUMES NEGLIGIBLE NC BG - NOT REALISTIC

15 ESTIMATES OF NC BACKGROUND  CC events (non oscillated) 1.0<E<8.0 GeV = 64, <E<40 GeV = 15,000 NC=0.3CC= 24,000 Assume flat y distribution ( q scattering), then E vis will have a uniform distribution from E to zero. This results in 19,300 events in 1.0<E vis <8.0 GeV, and with eff=0.85 we observe 16,400. Tufts scanning estimate % get into e sample. Scott Menary used 0.5% in his GLOBES calculations. Carl Bromberg’s scan - 2 of 265 NC’s get into e sample, 0.7%. Application of kinematic analyses (p T, m(  0 ),etc.), ionization, multivariate techniques,etc. should improve on 1.35%. If we take 1.35% as a worst case scenario (???), then NCBG=221 events and B= e + e +NC= =514

16 10 kton LArTPC at Soudan; e= < E < 8.0 GeV with ‘worst case’ NCBG sin 2 2  13 =0.10; sin2  13 =0.3162;  =0 S=6651.1x0.1x x x0.3162x0.85 = B=( )x =514  S=(S+2B) 1/2 = 41.1 ; (  S/S)= or sin 2 2  13 =  (was with no NCBG) 3 S.D. from zero limit corresponds to sin 2 2  13 = (was with no NCBG) NOvA +LArTPC(Soudan) 3 S.D. limit, S=100.7, and sin 2 2  13 = (compared to with no NCBG) (??) WE NEED A GOOD MC SIMULATION of NCBG in ON-AXIS WBB.

17 CP VIOLATION (neutrinos only) NOvA at Ash River, LArTPC at SOUDAN Sin 2 2  13 =0.10 ; 30x10 20 pot; S(  )= EV 1 +EV 2 +EV 3 (  )+EV 4 (  ) B L 1 (best case) B L 2 (worst case)  S N B N  S N S L B L 1 SL1 SL1 B L 2 SL2 SL  / “ “ 34.9 “ 40.7  / “ “ 33.9 “  / “ “ 33.7 “ 39.7  / “ “ 33.1 “  / “ “ 32.7 “  / “ “ 32.4 “  / “ “ 32.4 “ 38.6  “ “ 32.7 “  / “ “ 33.2 “  / “ “ 33.8 “  / “ “ 34.4 “  / “ “ 34.9 “  / “ “ 35.4 “  / “ “ 35.6 “  / “ “ 35.6 “  “ “ 35.3 “ 41.1

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20 TENTATIVE CONCLUSIONS-NEUTRINOS ONLY(3-5 yrs) 1) 10 kt LArTPC is as good for sin 2 2  13 at Soudan as at Ash River 2) CP violation - LArTPC at Soudan and NOvA at Ash River could give information on . (Both at Ash River tells nothing) 3) Thousands of events on-axis with which to study large LArTPC. 4) BUT we really need a good MC study of NC background in WBB. 5) Still to do - antineutrinos, matter effects, mass hierarchy, but by time antineutrinos run we want 50 kilotons & Project X - whole new story. 6) Other Physics Studies - Non-Standard Effects,e.g., Lorentz violation, nu decay - needs a broad energy spectrum such as WBB on-axis PRACTICAL MATTERS 1) Chances of getting funding for ~10kt prototype detector better if it contributes additional physics to NOvA. 2) A substantial surface building will be needed -- NOvA building not available (G.F.) - Large MINOS surface building at Soudan should be. 3) Could we go underground at Soudan - alleviate the CR background - safety problems ?? - cavern ?? - consult Minnesotans 4) etc. OTHER ALTERNATIVES - e.g., ~300km off-axis (different L and L/E)