Accelerator Neutrino Programme at Fermilab ∗
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FERMILAB-CONF-10-099-T Accelerator Neutrino Programme at Fermilab ∗ Stephen J. Parke Theoretical Physics Department, Fermi National Accelerator Laboratory P.O.Box 500, Batavia, IL 60510, USA parke@fnal.gov The accelerator neutrino programme in the USA consists primarily of the Fermilab neutrino programme. Currently, Fermilab operates two neu- trino beamlines, the Booster neutrino beamline and the NuMI neutrino beamline and is the planning stages for a third neutrino beam to send neutrinos to DUSEL. The experiments in the Booster neutrino beamline are miniBooNE, SciBooNE and in the future microBooNE, whereas in the NuMI beamline we have MINOS, ArgoNut, MINERVA and coming soon NOνA. The major experiment in the beamline to DUSEL will be LBNE. 1. Neutrino Standard Model The flavor content of the three neutrino mass eigenstates is given in Fig. 1. The current questions in this model are what is the size of 2 2 1 2 1 2 sin θ13; (sin θ23 ); (sin θ12 ); sign(δm ) and sin δCP (1) − 2 − 3 31 It is possible that the first three of these are related to some small parameter 2 2 like δm21/δm31 0:03 raised to some power, n. From current experiments the size of this power≈ is constrained to be larger than one, n > 1, except for 2 1 (sin θ23 ) where the lower bound is weaker, approximately n > 1=2. − 2 This could be due to some broken Tri-Bi-Maximal symmetry which would be very interesting and exciting. Another possibility is that it is coincidental which would be much less interesting from a theorists perspec- tive. ∗ Presented at Cracow Ephiphany Conference, January 5-8, 2010, Krakow, Poland. (1) 2 krakow_nus printed on April 9, 2010 Solar Sector: 12 { } 2 Νe ΝΜ ΝΤ Uαj | | cos ∆ $ cos ∆ $ 2 2 sinΘ sin Θ23 sin Θ12 13 2 5 2 3 1 2 1 "1 δmsol"1 = +7.6 10− eV Squared 2 2 2 5 2 sin Θ13 (msol × 2 δm 1= +7.6 10− eV (m 1 ! ! sol atm "1 Mass sinΘ13 × 2 2 3 2 sin Θ sinΘ13 12 1 2 δm = 2.4 10− eV 2 (matm 2atm 3 2 2 "1 |δm |= 2.4 ×10− eV (msol 2 atm sin Θ23 ! ! ! ! 1 1 Neutrino 1 3 | | × " Reactor/Acc2ele" rator 2Sector: 13 sinΘ 1 2 1 13 sin Θ13 δm2 / δm 2 0.03 NORMAL INVERTEDδm sol 30atmδm { } CPT invariant δ δ|| atm| ≈| ∗ | | ≈sol| ! ! ⇒ ↔ − 2 6 ∆ δm2 = 0.05 eV < m < 0.5 eV = 106 m Fractional Flavor Content varying cos δm atm= 0.05 eV < m <νi 0.5 eV = 10− −m e atm νi ∗ e∗ !22 " 2 Fig. 1. The flavor content5 2 of the neutrino mass eigenstates[1]. Thesin!sin widthθθ12 of12 the 11/3/3 " δmsol = +7.6 10− eV lines is used× to show how these fractions change as cos δCP varies from -1 to +1.∼∼ Of course, this figure must be the same for neutrinos and anti-neutrinos2 if CPT is 2 2 5 2 3 2 2 δm δm= +7.6conserved.=102−.4eV 10− eV sinsin θθ2323 11/2/2 sol| atm|× × ∼∼ 2 3 2 δmatm =2 2.4 102− eV2. Current Neutrino Program at Fermilab 22 | δm| sol / ×δmatm 0.03 sinsin θθ1313<<3%3% |2 | | 2 | ≈ δmatm 30 Currentlyδmsol there are two operating neutrino beamlines at Fermilab with | δ|m≈ 2 another∗ |= 0 being.05| eV proposed.< Thesem are< 0.5 eV = 10 6 m 2 atm νi 6 − 0e δ < 2π δmatm = 0.05 eV < mνi < 0.5 eV = 10− me ∗ 0 δ < 2π The Booster Neutrino Beamline∗ which uses 8 GeV protons≤≤ from the ! 2 • Booster. Currently only miniBooNE is taking data in this beamline ! msinν =θ12 1/3 " " i ∼ since SciBooNE has completed it's data taking and mircoBooNE is 2 f"1 cos2 θ 68%still in the approval process. ∼sin θ23" ≈ 1/2 2 ∼ NuMI (Neutrinos from the Main Injector) which uses 120 GeV protons f2 sin θ 32%• ∼sin2 θ" ≈< 3%from the main injector. This beamline sends neutrinos to the MINOS 13 near and far detectors. Also in the near detector hall is ArgoNut and MINERVA. ArgoNut is taking data and MINERVA will start 0 δ < 2πdata taking in 2010. The NOνA near and far detectors will also use ≤ neutrinos from this beamline.– Typeset by FoilTEX – 4 In addition there is a proposal to build a third neutrino beamline to • send a neutrino beam from Fermilab to DUSEL in the Homestake mine. This beamline will initially be powered by protons from the main injector but will eventually be powered by a– veryTypeset highby intensityFoilTEX – 1 proton beam (>2MW) from Project X. – Typeset by FoilTEX – 1 – Typeset by FoilTEX – 1 – Typeset by FoilTEX – 1 – Typeset by FoilTEX – 1 krakow_nus printed on April 9, 2010 3 2&&34"5)6"7%3+) •! 83+93:#;)3(9'%+"5):;%+7)) !"&5$'+<83:;%+;)9"=>+%?:",) %+=&:5%+7);.;9"$'@=;) •! A:&&)3;=%&&'@3+)>.B39>";%;) "C=&:5"5)'9)11D) •! 8EF)=3+;"#G%+7)B3%+9)H#3$) 9>")-IAJ*)+":9#%+3)'+'&.;%;) %;)4%9>%+)10D)=3+93:#) •! KL)(";9)M9)%;)'9)>%7>)G'&:",) CPT 5:")93)5"M=%9)'9)>%7>)"+"#7.) •! N+;>'5"5)#"7%3+)'#3:+5) $'C%$'&)$%C%+7)%;)"C=&:5"5) '9)11OPD)8OQO) more Anti-neutrino running NOW ! !"#$%&'()*"$%+'#,)-'.)/01) R"S)T'#9+"&&)<)N+%G"#;%9.)3H)*:;;"C)2 2 UV) Fig. 2. The δm32 v sin 2θ23 allowed region obtained using the anti-neutrinos in the neutrino beam. The CPT conserving point is within the 90% contour. MINOS has now finished a dedicated run with anti-neutrinos to tighten the contours on this plot. MINOS uses 120 GeV protons from the main injector with a nominal beam power of 300kW and currently has the world's best measurement of ∆m2 using the neutrino beam [2], j 32j ∆m2 = 2:43 0:13 10−3 eV2; (2) j 32j ± × and is currently running in anti-neutrino mode to check whether or not CPT is violated in the neutrino sector, see Fig.2. 4 krakow_nus printed on April 9, 2010 MiniBooNE and SciBooNE are measuring neutrino cross sections rele- vant for future neutrino experiments. Also, MiniBooNE is also looking for deviations from the three active neutrino Standard Model that has been assembled in the last ten years and in particular to confirming or refuting the LSND anomaly. No evidence in support of LSND has been found but a unexplained low energy excess in the 200 to 475 MeV was observed [3], Excess Events (200 to 475MeV ) = 128:8 20:4 38:3: (3) ± ± MiniBooNE appearance data show a low-energy excess While in the anti-neutrino !e channel the evidence for an excess is inconclusive. A.A. Aguilar-Arevalo et al., PRL 102, 101802 (2009) Excess from 200-475 MeV = 128.8+-20.4+-38.3 events 6.46E20 POT Excess Fig. 3. The excess events as seen in neutrino running at MiniBooNE. Between 200 and 475 MeV, a clear excess is seen. 2.1. NOνA The NOνA project consists of increasing the beam power in NuMI (Neu- trinos from the Main Injector) from 300 kW to 700 kW and to build the 15 kton liquid scintillator NOνA detector in Ash River, 810 km from Fermilab, so as to explore both P (νµ νe) and P (¯νµ ν¯e) at the sub 1% level. This 2 ! ! will put a limit on sin 2θ13 at the 0.01 level, see Fig. 4. This experiment will also give us the first glimpse of the neutrino mass hierarchy and/or the first restrictions of the range of the CP violating phase δCP , see Fig. 5. krakow_nus printed on April 9,2 2010 5 Sensitivity to sin (2!13) ! 0 Gary Feldman P5 Meeting 2 25 Fig. 4. The 90% sensitivity to sin 2θ13 for NOνA [4] assuming equal running time for neutrinos and anti-neutrinos. The blue (red) curves is for the normal (inverted) hierarchy. The three lines from right to left are for 0.7, 1,2 and 2.3 MW of protons on target respectively. These curves correspond to P (ν ν ) and P (¯ν ν¯ ) at µ ! e µ ! e the sub 1% level. Also the MINERvA experiment operating in the NuMI near detector hall will perform precision measurements of neutrino cross sections above 1 GeV on various nuclear targets. The information obtained from this experiment will be invaluable for future very long baseline neutrino oscillations. 2.2. The Physics of Long Baseline: νµ ! νe The amplitude for νµ νe can be simple written a sum of three ampli- tudes, one associated with! each neutrino mass eigenstate, 2 2 2 im1L=2E im2L=2E im3L=2E Uµ∗1e− Ue1 + Uµ∗2e− Ue2 + Uµ∗3e− Ue3: The first term can be eliminated using the unitarity of the MNS matrix and thus the appearance probability can be written as follows[6] 2 −i(∆32+δ) P (νµ νe) Patme + Psol : (4) ! ≈ p p Off-Axis Beams: BNL 1994 95% CL Resolution of the Mass 6 krakow_nus printed on April 9, 2010 Neutrino v Anti-Neutrino One Expt. Ordering NO!A Alone Proposed Experiments: NOvA 2 T2K sin 2θ13 sin δ + sin δ = 2 θ /θcrit 1.4 Narrow Beams! - Cou" −nting! Expts":− ! " ≈ ! 0.05 L=295 km and Energy at Vac. Osc. Max. (vom) 2 δm32 Evom = 0.6 GeV 3 2 2 2.5 10− eV sin 2θ Proposed Experiments: × 13 sin δ +! sin δ " = 2 θ /θcrit 0.47 ! " − ! "− ! " ≈ ! 0.05 2 Narrow Beams - Counting Expts: sin 2θ13 sin δ sin δ = 2 θ /θ 1.4 L=700 - 1000 km and + crit L=295 km and 2 ! " − ! "− ! " ≈ ! 0.05 Energyi.e.