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PHYSICS IN THE NuMI BEAM with a ~10 kiloton

LARTPC prototype

ASH RIVER or SOUDAN

J.Schneps

PRELIMINARY,UNFINISHED, & ROUGH

Sept. 27, 2007

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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).

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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 sin2213 by 2. Another advantage, if sin2213 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.

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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.

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e Oscillations

(Not including matter effects; - for nu, + for antinu)

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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NuMI ME Neutrino Beam Event Rates

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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AssumeLArTPC ready for start of NOvA in

ME Beam

30 X 1020 pot exposure to neutrinos

NOvA: 15 kilotons and 40% efficiency for e

LArTPC: 10 kilotons and 85% eff. for e

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15 kiloton NOA; 30x1020pot; =40%; L=810kmsin2213=0.10; m21

2=8x10-5 eV2; m312=2.5x10-3 eV2

E(GeV) CC

(100%)

e CC

(100%) EV1 EV2 EV3/sin EV4/cos eB eB

nc

1.0-1.2 96.5 1.70 1.00 0.09 - 0.43 - 0.42

1.2-1.4 154.2 2.43 2.59 0.10 - 0.95 - 0.42

1.4-1.6 321.4 3.04 6.30 0.16 - 2.00 - 0.28

1.6-1.8 802.7 3.16 16.05 0.31 - 4.46 0.00

1.8-2.0 1669.9 3.89 32.06 0.52 - 7.99 1.80

2.0-2.2 1991.3 4.38 35.05 0.51 - 7.96 2.86

2.2-2.4 1349.0 5.11 22.12 0.29 - 4.56 2.17

2.4-2.6 642.5 4.87 9.51 0.12 - 1.82 1.07

2.6-2.8 321.4 5.11 4.24 0.05 - 0.74 0.53

2.8-3.0 192.7 4.62 2.31 0.02 - 0.38 0.30

3.0-3.2 128.5 4.87 1.39 0.02 - 0.22 0.20

3.2-3.4 64.2 4.50 0.64 0.01 - 0.08 0.10

Totals 7734.3 47.7 133.3 2.2 - 31.6 7.9 19.1 1.9 7.0

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NOvAFor =0, signal S=133.3+2.2+7.9=143.4 background B=19.1+1.9+7.0= 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 (sin2213)/ sin2213

or sin2213=0.1000 0.0098 (~10 s.d. from zero)

LARTPC(Ash River) S=143.4x(2/3)x(.85/.40)= 203.1 B=(19.1+1.9)x(2/3)x(.85/.40)=29.7 (no NC) (S/S)=(16.2/203.1)=0.080

sin2213=0.1000 0.0080 (~12.5 s.d. from zero)

NOvA+ LARTPC ; sin2213=0.1000 0.0062 (16 s.d from zero)

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3 S.D. Sensitivity Limiits for =0

or

NOvA B=28.0 S=27.4 corresponds to

sin2213 = 0.0165LArTPC B=29.7 S=28.1 corresponds to

sin2213 = 0.0112NOvA + LArTPC B=57.7 S=37.0 corresponds to

sin2213 = 0.0082We have omitted various systematic errors, e.g. ,E, uncertainties in e beam,NC background,etc., so results are optimistic but “in the ballpark”.

€

SS

=S + 2B

S=

1

3

€

S2 − 9S −18 = 0

€

S =9 + 81+ 72B

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10kton LArTPC; L=735 km; ME Beam on-axis; 30x1020 pot; eff.=100%; sin2213=1.0;

m212 = 8x10-5 eV2; m31

2 = 2.5x10-3 eV2

E(GeV) CC e CC e CC EV1 EV2 EV3/sin EV4/cos

1.0-1.2 48.6 0.97 0.29 17.6 0.11 - 2.19 - 1.34

1.2-1.4 69.7 1.27 0.29 32.8 0.11 - 3.43 - 0.79

1.4-1.6 115.1 1.88 0.62 57.6 0.14 - 5.27 0.08

1.6-1.8 151.6 2.20 0.57 72.8 0.15 - 5.87 1.19

1.8-2.0 230.3 3.11 0.49 101.8 0.18 - 7.27 2.62

2.0-2.2 343.8 4.06 0.55 139.3 0.22 - 9.19 4.48

2.2-2.4 475.9 4.90 0.75 171.9 0.24 -10.10 6.28

2.4-2.6 619.5 5.27 0.50 198.3 0.28 -10.86 8.17

2.6-2.8 785.7 5.89 0.52 226.9 0.31 -11.68 9.85

2.8-3.0 973.0 6.52 0.62 252.2 0.33 -12.04 11.55

3.0-3.2 1152.2 7.14 0.65 266.4 0.33 -11.75 12.54

3.2-3.4 1330.5 7.72 0.72 281.1 0.35 -11.78 13.79

3.4-3.6 1493.5 8.51 0.76 237.1 0.33 -10.98 13.97

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E(GeV) CC e CC e CC EV1 EV2 EV3/sin EV4/cos

3.6-3.8 1633.8 8.82 0.75 284.4 0.33 -10.38 14.21

3.8-4.0 1772.4 9.39 0.64 277.9 0.32 - 9.78 14.22

4.0-4.2 1897.3 9.87 0.99 276.7 0.30 - 9.19 14.27

4.2-4.4 1983.2 10.11 0.97 268.2 0.28 - 8.29 13.92

4.4-4.6 2094.3 10.47 0.75 261.8 0.29 - 8.06 14.36

4.6-4.8 2224.9 10.68 1.16 258.3 0.29 - 7.44 13.76

4.8-5.0 2340.0 11.23 0.91 247.6 0.26 - 6.65 13.31

5.0-5.2 2387.0 11.22 0.91 231.1 0.26 - 6.39 13.17

5.2-5.4 2520.0 11.59 0.97 227.6 0.25 - 5.90 12.64

5.4-5.6 2575.1 11.59 0.89 216.5 0.26 - 5.60 12.49

5.6-5.8 2723.5 12.26 0.71 217.9 0.22 - 5.01 11.83

5.8-6.0 2781.1 12.51 1.36 211.5 0.22 - 5.11 12.09

6.0-6.2 2905.9 13.08 1.00 198.9 0.20 - 4.38 11.17

6.2-6.4 2914.1 12.82 1.14 188.9 0.20 - 4.38 10.71

6.4-6.6 3035.7 12.75 1.27

175.5 0.18 - 3.54 9.64

6.6-6.8 3035.7 11.54 1.33 170.4 0.18 - 3.54 9.64

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sin2213=1.0 ; =100%

E(GeV) CC e CC e CC EV1 EV2 EV3/sin EV4/cos

6.8-7.0 3121.6 11.55 0.95 170.0 0.19 - 3.66 9.91

7.0-7.2 3155.7 11.68 1.01 161.6 0.19 - 3.16 9.49

7.2-7.4 3120.0 11.86 0.93 149.9 0.16 - 2.61 8.34

7.4-7.6 3069.7 13.81 1.10 147.5 0.15 - 2.56 8.21

7.6-7.8 2959.5 13.61 1.32 133.2 0.15 - 2.47 7.92

7.8=8.0 2850.8 15.10 0.69 119.9 0.11 - 1.91 6.67

TOTALS 64890.7 317.0 28.1 6651.1 8.07 - 232.4 334.4

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10 kton LArTPC at Soudan; =0.851.0 < E < 8.0 GeV

sin2213=0.10; sin213=0.3162; =0S=6651.1x0.1x0.85+8.07x0.85+334.4x0.3162x0.85 = 662.1B=(317.0+28.1)x0.85=293.3 (assumes no NCBG)S=(S+2B)1/2= 35.4 ; (S/S)=0.053 or

sin2213=0.10000.0053

3 S.D. from zero limit

corresponds to sin2213=0.0080

NOvA +LArTPC(Soudan) 3 S.D. limit, S=80.7,

And sin2213=0.0066BUT ASSUMES NEGLIGIBLE NC BG - NOT REALISTIC

€

S =9 + 81+ 72B

2= 77.3

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ESTIMATES OF NC BACKGROUND

CC events (non oscillated) 1.0<E<8.0 GeV = 64,890 8.0<E<40 GeV = 15,000NC=0.3CC= 24,000

Assume flat y distribution (q scattering), then Evis will have a uniform distribution from E to zero. This results in 19,300 events in 1.0<Evis<8.0 GeV, and with eff=0.85 we observe 16,400.

Tufts scanning estimate - 1.35% 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 (pT, 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= 293+221=514

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10 kton LArTPC at Soudan; e=0.851.0 < E < 8.0 GeV with ‘worst case’ NCBG

sin2213=0.10; sin213=0.3162; =0S=6651.1x0.1x0.85+8.07x0.85+334.4x0.3162x0.85 = 662.1B=(317.0+28.1)x0.85+221=514 S=(S+2B)1/2= 41.1 ; (S/S)=0.0062 or

sin2213=0.10000.0062 (was 0.0053 with no NCBG)

3 S.D. from zero limit

corresponds to sin2213=0.0112 (was 0.0080 with no NCBG)

NOvA +LArTPC(Soudan) 3 S.D. limit, S=100.7,

and sin2213=0.0092 (compared to 0.0066 with no NCBG) (??)

WE NEED A GOOD MC SIMULATION of NCBG in ON-AXIS WBB.

€

S =9 + 81+ 72B

2=100.8

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CP VIOLATION (neutrinos only)NOvA at Ash River, LArTPC at SOUDAN

Sin2213=0.10 ; 30x1020 pot; S()= EV1+EV2+EV3()+EV4()

BL1(best case)

BL2(worst case)

SN BN SN SL BL1 SL

1 BL2 SL

2

0 143.4 28.0 14.1 662.0 293.3 35.3 514 41.1

/8 130.7 “ 13.7 631.3 “ 34.9 “ 40.7

/4 118.8 “ 13.2 561.5 “ 33.9 “ 39.9

3/8 109.3 “ 12.9 548.8 “ 33.7 “ 39.7

/2 103.9 “ 12.6 509.7 “ 33.1 “ 39.2

5/8 103.3 “ 12.6 480.0 “ 32.7 “ 38.8

3/4 107.4 “ 12.8 464.4 “ 32.4 “ 38.6

7/8 116.1 “ 13.1 465.2 “ 32.4 “ 38.6

127.6 “ 13.5 482.3 “ 32.7 “ 38.9

9/8 140.3 “ 14.0 513.0 “ 33.2 “ 39.3

5/4 152.2 “ 14.4 552.8 “ 33.8 “ 39.8

11/8 161.7 “ 14.8 595.5 “ 34.4 “ 40.3

3/2 167.1 “ 14.9 634.6 “ 34.9 “ 40.8

13/8 167.7 “ 15.0 664.3 “ 35.4 “ 41.1

7/4 163.6 “ 14.8 679.9 “ 35.6 “ 41.3

15/8 154.9 “ 14.5 679.1 “ 35.6 “ 41.3

2 143.4 “ 14.1 662.0 “ 35.3 “ 41.1

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TENTATIVE CONCLUSIONS-NEUTRINOS ONLY(3-5 yrs)1) 10 kt LArTPC is as good for sin2213 at Soudan as at Ash River2) 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 timeantineutrinos 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)