Is Sin22

• At certain values of m2 and integrated p.o.t., MINOS can achieve a tighter limit on sin22 than Super-K.

• This implies that we could exclude sin22 at <90% C.L if the parameters are favourable.

• Why is this interesting?– Implications for theoretical models?

– Ambiguity in measurement of sin22 if sin22<1 (U

is double-valued)

D.A. Petyt Dec’ 03

2

2sin11)1(42sin

22222

UUU

Sin22m2=0.002 eV2

is minimised w.r.t. m2. C.L. intervals are drawn assuming 1 d.o.f.

Fits along the SK 90% CL contour

See http://www.physics.umn.edu/~petyt/cc/pacnov03/stplot1/sklim.ps for more fits

Discrimination as a function of m2 and p.o.t.

C.L. discrimination requires more than 7.4e20 p.o.t.

Assuming surface scales as N, can calculate integrated p.o.t. required to exclude sin22=1 at 68,90,99% C.L.

Sin22discrimination, 7.4e20 p.o.t.

Sin22discrimination, 16e20 p.o.t.

Sin22discrimination, 25e20 p.o.t.

C.L. (3 discrimination possible in a small portion of S-K 90% C.L region

Summary• It is possible to exclude sin22at >90% C.L. in

the following circumstances:– The value of m2 is greater than 0.0018 eV2

– The value of sin22 is at, or close to, the current S-K 90% lower bound

– Total integrated p.o.t. > 7.41020

• There is a (very) small part of the S-K 90% allowed region where we can exclude sin22at >99% (assuming 251020 p.o.t.)

• Life would be much better if the mean value of L/E for MINOS were lower by a factor of 2– Should be an easier measurement off-axis