Prospects and progress: new experimental searches for - - PowerPoint PPT Presentation
Prospects and progress: new experimental searches for neutron-antineutron oscillations and related probes for new physics INT-17-69W A. R. Young Neutron Oscillation: appearance NCSU disappearance and baryogensis Thanks to J. Barrow, M.
NCSU
Thanks to J. Barrow, M. Frost,
PPSN 2018 ILL, May 24, 2018
INT-17-69W
Neutron Oscillation: appearance disappearance and baryogensis
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All Connected by
models at higher energy scales …
quark sector for baryogenesis
possible in the SM through B-L conserving excitations (sphalerons)
→ electrowk scale (SUSY) & B-L? → leptogenesis and B-L?
Also fjnd B-violation in GUTS ΔB=1: p decay → Λ > 1013 T eV strong exptl limits… ΔB=2: not constrained by
p decay Provides viable path to observed BAU through, e.g. Post Sphaleron baryogenesis!
scale models like MSUSY and RPV SUSY predictions
LHC-u like di-quarks and the scalars in PSB models)
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Important and unique process to probe B violation and baryogenesis mechanisms at relevant energy scales
Very limited selection! Cold Neutron Beams ofger a clean and powerful probe for this physics
Can add to this short list... with factor of 1000+ gain in sensitjvity possible!
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role in particle physics
understanding CP-violation in SM
2/mW 2)
→ fjrst indication of top mass 1987
understanding the neutrino sector
Somewhat natural to expect that N-N oscillations can provide extremely sensitive probe for new physics. In fact, current sensitivity to couplings of order 4x10-23 eV (comparable to EDM measurements)...
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Current limit on α ≈ 4×10-29 MeV, or τnn = ħ/α ≈ ~1×108 s (free neutron)
free condition holds (Vt/ħ << 1)
substantial cancellation of Bearth
cross-checked with magnetic fjeld (“switch ofg” oscillations with Bearth)
Baldo-Ceolin et al, Z.Phys. C63 (1994) 409-416
neutron oscillatjons
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ROx = 5×1022 s-1
Free neutron beam search goal at European Spallatjon Source CNN DUNE analysis No background
Josh Barrow’s presentation!
Currently limited by atmospheric neutrino backgrounds Decay products signifjcantly “processed” by heavy nuclei – background rejectjon challenging!
Model dependent input → R “suppression factor”
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ROx = 5×1022 s-1
Free neutron beam search goal at European Spallatjon Source CNN DUNE analysis 0 background
Josh Barrow’s presentatjon! Model dependent input → R “suppression factor” → Other exotjc decay modes have very similar signatures → Nuclear Environment can result in suppression or enhancement in some models Intranuclear decay measurements complementary to CN beams!
Increase number of neutrons Increase tjme of fmight Keep (or increase) detectjon effjciency (50%) Keep background at zero (need improved dets!) Betuer BEarth suppression
Optjmizatjon requires remarkable facility...
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Preparations to test accelerator systems at end of summer are under way and the slab for the accelerator-to-monolith structure was just poured…
Lower moderator volume available
for optimized (LD2?) source for N-Nbar
Large beam port allows, in
principle, roughtly 2 orders of magnitude more integrated fmux in beam!
Very bright, “pancake moderator”
in top position
and space for 200m beam-line...
Current plan:
experiments by friendly users
with public users; establish basis for future cost sharing – full instrument set is 22 instruments – 15 instruments are under construction – 8 instruments are part of “hot commissioning” in 2022
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N-Nbar@ESS
2018–2025: – R&D as a part of joint ANNI/HI-BEAM instrument proposal – develop full proposal compatible with as-built ESS
2025+: Mount experiment!
Gustaaf Brooijmans Neutron-Anti-Neutron Oscillation Search
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See e.g. NNbarX (Babu et al.), htup://arxiv.org/abs/arXiv:1310.8593
MC optjmizatjon of parameters ongoing!
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increasingly large momentum transfers
Ni refmectjvity → 0 defjnes m=1
(Swiss Neutronics) Actjve R&D at Nagoya University, with devices used at JPARC
Current work characterizing magnetjc noise Current work characterizing magnetjc noise
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neutrons
Gustaaf Brooijmans Neutron-Anti-Neutron Oscillation Search
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cosmic veto cosmic veto
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G4-based
Identjfy Target Improvements over ILL
acceptance ~90% (x1.8) X3 red. in tjming window (50 ns)
Recent developments in Detector Development!
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x 1000 in probability, reach τ ~ 2-3 x 109 s
Brightness ≥ 1 Moderator area Needs large aperture 2 Angular Acceptance Quadratic sensitivity 40 length Scale with t2, so L2 5 Run Time ILL run was 1 year 3 Total ≥ 1000
Many sources of gain not taken, but fjnal geometry of lower moderator and port not established
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Assumptjons:
Lower moderator: LD2 optjmized for
integrated fmux
No obstructjons in large beam port
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During 5 days of workshop 36 partjcipants delivered 40 presentatjons!
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At ESS: initjatjng coordinated approach to partjcle physics R&D at ESS, including a joint HIBEAM and ANNI proposal for fundamental neutron physics at ESS In Partjcle Physics Community: Contribute partjcle physics roadmaps and a encourage a culture-shifu in the expectatjons for medium scale partjcle physics experiments to include the possibility of sitjng experiments at traditjonally scatuering laboratories (we already do this...) Refocus R&D on productjve experiments: We have several, potentjally high impact experiments that can mounted on current cold neutron or ultracold neutron facilitjes N-Nbar: Ballistjc and collision-compensated geometries possible (Nesvizhevsky)! Strong cold neutron beams available at several facilitjes Very strong UCN sources (PNPI Super Source) essentjally ready for commissioning! N-N’ resonant and transitjon magnetjc moment searches Proposal in preparatjon at ORNL
Berezhiani and Kamyshkov, Possibly relevant to lifetjme, Limits exprimentally feasible
P07: Takuyu Hosobata 9m elliptjcal optjc being tested at J-PARC Optjcs: (Shimizu-group, Hino-group, RIKEN,...) Detectors (proto-type system for evaluatjon identjfjed) (Stockholm and Lund group) Event generators (Golubeva et al.), new signatures and couplings to new physics, as well as a cornucopia of new ideas... (Kamyshkov group) characterizing impact of magnetjc fjeld fmuctuatjons, etc..
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and improve the project!
and the Underground Physics program
is underway Opportunitjes to gain a factor 1000 in sensitjvity to processes at core of our existence and understanding of universe are rare
Should not be squandered
htup://www.nnbar-at-ess.org