Transcript ppt
The NOnA Experiment P5 Meeting SLAC 21 February 2008 Gary Feldman Gary Feldman P5 Meeting 21 February 2008 0 What is NOnA? NOnA is a second-generation experiment on the NuMI beamline, which is optimized for the detection of nm ne oscillations. It will give an order of magnitude improvement over MINOS in measurements of ne appearance and nm disappearance. NOnA is a “totally active” tracking liquid scintillator calorimeter, sited off-axis to take advantage of a narrowband beam. The NOnA project also includes accelerator upgrades to bring the beam power from 400 kW to 700 kW. NOnA’s unique feature is its long baseline, which gives it sensitivity to the neutrino mass ordering. NOnA is complementary to both T2K and Daya Bay. Gary Feldman P5 Meeting 21 February 2008 1 NOnA Site Ash River International Falls Duluth Voyageurs National Park (shaded brown) Minneapolis Fermilab Ash River The Ash River site is the furthest available site from Fermilab along the NuMI beamline. This maximizes NOnA’s sensitivity to the mass ordering. Gary Feldman P5 Meeting 21 February 2008 2 NOnA Basic Detector Element Liquid scintillator in a 4 cm wide, 6 cm deep, 15.7 m long, highly reflective PVC cell. Light is collected in a U-shaped 0.7 mm wavelength-shifting fiber, both ends of which terminate in a pixel of a 32-pixel avalanche photodiode (APD). The APD has peak quantum efficiency of 85%. It will be run at a gain of 100. It must be cooled to -15oC and requires a very low noise amplifier. Gary Feldman P5 Meeting 21 February 2008 3 Far Detector The cells are made from 32-cell extrusions. 12 extrusion modules make up a plane. The planes alternate horizontal and vertical. There are 1003 planes, for a total mass of 15 kT. There is enough room in the building for 18 kT, which can be built if we can preserve half of our contingency. The detector can start taking data as soon as blocks are filled and the electronics connected. An admirer Gary Feldman P5 Meeting 21 February 2008 4 NOnA Timeline May 2002 Jun 2002 Mar 2004 Mar 2005 Apr 2005 Nov 2005 Feb 2006 Oct 2006 May 2007 Oct 2007 May 2008 Nov 2008 Apr 2009 Jun 2011 Aug 2012 Jan 2014 Gary Feldman 1st Workshop Letter of Intent Proposal to the Fermilab PAC Revised Proposal to the PAC Fermilab Stage 1 Approval CD-0 Granted Recommended by NuSAG Recommended by P5 CD-1 Granted Passed CD-2/3a Review CD-2/3a Granted CD-3b Granted Start of Construction Far Detector Building Beneficial Occupancy 1st 2.5 kT of the Far Detector Online Full Far Detector Online P5 Meeting 21 February 2008 5 Funding Profiles With this profile, we could advance the schedule by 10 months. Gary Feldman P5 Meeting 21 February 2008 6 Reactor vs. Accelerator 2 sin2(q23) vs. sin2(2q23) Peter explained the physics of neutrino oscillations well, so I need not repeat it. However, I would like to expand on a couple of points. 1.4 1.3 Reactor and accelerator experiments do not measure the same thing. Reactors are sensitive to sin2(2q13), while accelerators are sensitive to sin2(q23) sin2(2q13). If q23 ≠ p/4, these quantities can be quite different. 2 sin2(q23) 1.2 1.1 1.0 0.9 0.8 0.7 The good news is that a comparison of NOnA and Daya Bay can break this ambiguity and determine whether n3 couples more to nm or nt. Gary Feldman P5 Meeting 0.6 0.90 0.92 0.94 0.96 0.98 1.00 21 February 2008 sin2(2q23) 7 95% CL Resolution of the q23 Ambiguity The ambiguity can be resolved in the region below and to the right of the curves. The sensitivity depends on the mass ordering, d, and the sign of the ambiguity itself. The curves represent an average over these parameters. Gary Feldman P5 Meeting 21 February 2008 8 Measurement of 2 sin (2q23) This calculation uses NOnA’s excellent energy resolution on nm CC events. It is a parameterized calculation, which needs to be redone with a full reconstruction. Gary Feldman P5 Meeting 21 February 2008 9 Sensitivity to sin2(2q13) ≠ 0 Gary Feldman P5 Meeting 21 February 2008 10 Parameters Consistent with a 2% nm ne Oscillation Probability Gary Feldman P5 Meeting 21 February 2008 11 Strategy for Determining the Mass Ordering If the CP-violating term goes in the same direction as the matter effect, then there is no ambiguity and NOnA can determine the mass ordering by itself, given sufficient integrated beam. If the CP-violating term goes in the opposite direction as the matter effect, then there is an inherent ambiguity and NOnA cannot determine the mass ordering by itself. But it can be determined, in principle, by comparing NOnA and T2K. If the neutrino oscillation probability is larger in NOnA than in T2K, it is the normal mass ordering; if the opposite, it is the inverted mass ordering. Gary Feldman P5 Meeting 21 February 2008 12 95% CL Resolution of the Mass Ordering NOnA Alone Normal Ordering Gary Feldman P5 Meeting Inverted Ordering 21 February 2008 13 Combining Data with T2K When it is useful to combine data with T2K, I will assume that T2K will only run a neutrino beam because This is what they have proposed to do. They have less incentive to run antineutrinos since They have too short a baseline to get information on the mass ordering. The antineutrino rates at T2K energies are relatively somewhat lower than at NOnA energies. The complementarity between the two experiments is better statistically if T2K runs only neutrinos since it consists of comparing like runs — neutrinos to neutrinos or antineutrinos to antineutrinos. Gary Feldman P5 Meeting 21 February 2008 14 95% CL Resolution of the Mass Ordering NOnA Plus T2K Normal Ordering Gary Feldman P5 Meeting Inverted Ordering 21 February 2008 15 d vs. q13 Contours: Best Possible d Gary Feldman P5 Meeting 21 February 2008 16 d vs. q13 Contours: Worst Possible d T2K and NOnA Alone Profiles, not limits Gary Feldman P5 Meeting 21 February 2008 17 d vs. q13 Contours: Worst Possible d T2K and NOnA Combined Gary Feldman P5 Meeting 21 February 2008 18 Conclusions I Due to its long baseline and ease of running antineutrinos, NOnA will produce important results unavailable from any other experiment in its time frame. It is complementary to both T2K and Daya Bay. What was to become NOnA had its first workshop in May 2002. It has now passed all of its reviews and is ready to start construction in the spring of 2009, assuming funding will be available. All of the other major US neutrino accelerator initiatives being discussed today are in the workshop phase. Gary Feldman P5 Meeting 21 February 2008 19 Conclusions II NOnA will be the anchor of the US accelerator neutrino program. In addition to its unique physics contributions, It will provide the incentive to increase the NuMI beam power from 400 to 700 kW, and then to either 1.2 MW (SNuMI) or 2.3 MW (Project X), depending on available funding. It will provide a base detector, allowing the necessary liquid argon prototype, LAr5, to double the capacity of NuMI program. It will provide the continuity necessary to keep the program running smoothly, e.g. training experimental and accelerator physicists. Gary Feldman P5 Meeting 21 February 2008 20 Backup Slides Gary Feldman P5 Meeting 21 February 2008 21 What NOnA Can Do If … sin2(2q13) 0.1 Determine the mass ordering for half of the d space at the 1-3 s level; combining with T2K, determine the mass ordering for the other half of the d range at 1-2 s level. Exclude about half of the d space at the 1-2 s level. Combining with Daya Bay, determine whether n3 couples more strongly to nm or nt at the 2 s level if sin2(2q23) < 0.97. Gary Feldman P5 Meeting 21 February 2008 22 What NOnA Can Do If … sin2(2q13) 0.06 Determine the mass ordering for half of the d space at the 1-2 s level; combining with T2K, determine the mass ordering for the other half of the d range at 1-2 s level. Exclude about half of the d space at the 1-2 s level. Combining with Daya Bay, determine whether n3 couples more strongly to nm or nt at the 2 s level if sin2(2q23) < 0.94. Gary Feldman P5 Meeting 21 February 2008 23 What NOnA Can Do If … sin2(2q13) 0.03 Determine the mass ordering for a quarter of the d space at the 1 s level. Exclude about half of the d space at the 1-2 s level. Gary Feldman P5 Meeting 21 February 2008 24 What NOnA Can Do If … sin2(2q13) 0.01 See a signal at the 1-3 s level, confirming weak signals seen in other experiments. Gary Feldman P5 Meeting 21 February 2008 25 What We Know and What We Don’t Know Know to some extent Don’t know O. Mena and S. Parke, hep-ph/0312131 Gary Feldman P5 Meeting 21 February 2008 26 NOnA Near Detector The Near Detector will be placed in a cavern off of the MINOS access tunnel on the same off axis line as the far detector. 14.4 m 4.1 m Muon catcher 1 m iron 209 T 126 T totally active 23 T fiducial Shower containment region Target region 2.9 m Gary Feldman Veto region P5 Meeting 21 February 2008 27 Event Quality Longitudinal sampling is 0.15 X0, which gives excellent m-e separation. A 2-GeV muon is 60 planes long. Gary Feldman P5 Meeting 21 February 2008 28 ne CC event nepe-pp+ En=2.5GeV Ee=1.9GeV Ep=1.1GeV Ep=0.2GeV Gary Feldman P5 Meeting 21 February 2008 29 Background NC event nmNnmppo En=10.6 GeV Ep=1.04GeV Epo =1.97GeV Gary Feldman P5 Meeting 21 February 2008 30