1 ACFI Workshop “Beta decay as a probe of new physics” My hope for the workshop: Convey to theorists that there is discovery potential, but we can’t do it without their help. Outlook for precision beta ‐ decay experiments
2 Outlook for precision beta ‐ decay measurements Talk at ACFI Workshop “Beta decay as a probe of new physics” Outlook for precision beta ‐ decay experiments
3 Beta decay Amazing history: first steps beyond E&M Transmutations in decays Parity violation Gauge theories Unification … Is there a future for exploring? Precision frontier may hold surprises Outlook for precision beta ‐ decay experiments
4 Chirality ‐ flipping as means of detection of new physics. Leptoquarks: Small contribution that X: scalar; Y: Vector could be detected with Predicted by precision experiments Grand Unified Theories Predicted by Supersymmetric Theories Profumo, Ramsey ‐ Musolf, Tulin Phys. Rev. D 75 , 075017 (2007) Bhattacharya et al. Phys. Rev. D 94 , 054508 (2016) Or maybe something not considered so far… Outlook for precision beta ‐ decay experiments
Yang and Lee 5 Nuclear beta decay phenomenology: beyond V ‐ A ? Leptonic Standard Model Right ‐ handed + non ‐ SM ‐ LL � Ψ � � � � � � ′ �̅ � � �,� � �� � � � � � � ′ �̅ � � �,� � �� � � � � � �,� � � Ψ ���,� � � �� � � � � � � � � � � � � � chirality flipping � � � � � ′ �̅ � � � � �� � � � � � � ′ �̅ � � � � �� � � � � Ψ � � �,� � � Ψ Scalar, Tensor ���,� � �1 � � � � � � �� � � � Outlook for precision beta ‐ decay experiments
6 Example: Decay rate for non polarized axial (GT) decay � � �′ � � � � � 1 3 1 � � � �� � �� � 1 � � � � � ⋅ � � � � � � � � 2 � � ‐ correlation � � � � � � � � � � � � � � ′ /� � Fierz interference “ � � � correlation experiments” All correlation experiments � �� �� ⋅ �� �� show some sensitivity to the measure ratio: ��� �� interference �� Outlook for precision beta ‐ decay experiments
7 Polarized parent: more observables. ‐ asymmetry ‐ asymmetry ‐ Fierz � �� � �� � 1 � � � � � ⋅ � � � � � � � � � � · � � � � � � � � � � � � � � � � � � � … and the “letter soup” extends with observation of the electron polarization… Outlook for precision beta ‐ decay experiments
8 Nuclear beta decay phenomenology: beyond V ‐ A ? Leptonic Standard Model Right ‐ handed + non ‐ SM ‐ LL � Ψ � � � � � � ′ �̅ � � �,� � �� � � � � � � ′ �̅ � � �,� � �� � � � � � �,� � � Ψ ���,� � � �� � � � � � � � � � � � � � chirality flipping � � � � � ′ �̅ � � � � �� � � � � � � ′ �̅ � � � � �� � � � � Ψ � � �,� � � Ψ Scalar, Tensor ���,� � �1 � � � � � � �� � � � Helicity overlap � � interference: � � Outlook for precision beta ‐ decay experiments
9 Comparison with the LHC: the EFT “blow” Vincenzo et al. brought us in comparison with the LHC. Before: hard to compare, we thought model dependency implied nuclear sensitivity could be higher than hep experiments. Cirigliano et al. PPNP 71 , 93 (2013) Outlook for precision beta ‐ decay experiments
Comparison with the LHC: the EFT “blow” 10 V. Cirigliano et al. have established a connection between hep and beta ‐ decay observables via EFT. Assuming only left ‐ handed � ’s: From Bhattacharya et al. Phys. Rev. D 94 , 054508 (2016) Rough result of analysis of LHC limits: � � � � ��10 �� � Outlook for precision beta ‐ decay experiments
11 Beta decay sensitivity could reach beyond LHC. Outlook for precision beta ‐ decay experiments
12 Beta decay with nuclei: Confining radioactivity helps measuring kinematics Trapping can also allow polarization Amazing atom and ion traps have come a long way! Initial developments: Berkeley, Stony Brook, TRIUMF (atoms) CERN, Argonne, CAEN, TRIUMF (ions) What follows are vignettes showing aim of some groups (not complete…) Outlook for precision beta ‐ decay experiments
Ion trap at Hebrew University of Jerusalem and Racah Institute 13 Thanks: Guy Ron Outlook for precision beta ‐ decay experiments
Ion trap at Hebrew University of Jerusalem and Racah Institute 14 Thanks: Guy Ron Outlook for precision beta ‐ decay experiments
Ion trap at Hebrew University of Jerusalem and Racah Institute 15 Thanks: Guy Ron Outlook for precision beta ‐ decay experiments
TRIUMF atomic trap 16 Thanks: John Behr, Dan Melconian Outlook for precision beta ‐ decay experiments
CERN ion trap 17 Aim: little ‐ a to 32 Ar Decay at WISArD better than 0.1% 32 Ar Bertram Blank et al. – CEN Bordeaux ‐ Gardignan N. Severijns et al. – KU Leuven D. Zakoucky et al. – NPI Rez Instead of detecting E. Lienard et al. – LPC CAEN 31 S+p the neutrino 32 Cl Detect proton that contains info about the 32 Cl recoil (Doppler) Thanks: Bertram Blank Outlook for precision beta ‐ decay experiments
ANL trap: A=8 experiments 18 Delivery of 8 Li/ 8 B to BPT • Gas target geometry better matched to reactions • New gas catcher optimized to handle lighter masses and space-charge issues 8 Li: 7 Li(d,p) 8 Li 8 B: 6 Li( 3 He,n) 8 B Upgrades resulted in 10 × increase in ion delivery to BPT measure 8 B to study decay correlations + recoil ‐ order terms revisit 8 Li with 10 × higher statistics Thanks: Guy Savard Outlook for precision beta ‐ decay experiments
ANL trap: A=8 experiments 19 Plastic DSSD scintillator 8 Li + Spectrum from events with β and α particles Ion trap to hold the A=8 nuclei. ’s detected on the top and bottom detector. and ’s are measured with streep Si (a) Energy difference along with the fit to the simulated spectrum and the normalized detectors. residual. The gray curve shows the expected Hit locations allow tracking back to spectra for a pure T interaction. the emission point. Thanks: Guy Savard Outlook for precision beta ‐ decay experiments
20 Thanks: Maxime Brodeur Outlook for precision beta ‐ decay experiments
Texas A&M ion trap: TAMU 21 Thanks: Dan Melconian Outlook for precision beta ‐ decay experiments
Seattle ‐ ANL atomic trap 22 Goal: measure “little a ” to 0.1% in 6 He • • Laser cooling and trapping of 6 He Detect electron and 6 Li in coincidence • E-E scintillator system for e. • Micro-channel plate detector for 6 Li. • 19 discrepancy with atomic theory on charge distribution: Phys. Rev. A 96 , 053411 (2017) Outlook for precision beta ‐ decay experiments
Beta spectra 23 From above: most sensitive measurement could be spectra. � � (Look for Fierz interference distortion � � ) spectrum Warning: spectra are known to be difficult to measure. Fierz interf. Typical setup: magnetic spectrometer… Difficult to overcome systematic uncertainties. Outlook for precision beta ‐ decay experiments
Beta spectra implantations into scintillators 24 Thanks: Oscar Naviliat ‐ Cuncic Outlook for precision beta ‐ decay experiments
Beta spectra implantations into scintillators 25 Thanks: Oscar Naviliat ‐ Cuncic Outlook for precision beta ‐ decay experiments
Beta spectra CRES technique 26 In principle: allows determination of the beta energy at creation. Seattle ‐ ANL ‐ PNNL ‐ NCSU ‐ Tulane He6 ‐ CRES collaboration. Measure 6 He, 19 Ne, 14 O. Outlook for precision beta ‐ decay experiments
27 Neutron beta decay. After many years of developments, many recent important results… Vignettes follow. Outlook for precision beta ‐ decay experiments
Neutron lifetime 28 Thanks: Fred Wietfledt Outlook for precision beta ‐ decay experiments
Neutron lifetime 29 Thanks: Fred Wietfledt Outlook for precision beta ‐ decay experiments
The UCN Global fit into a single exponential function (blinded number) neutron lifetime experiment R. W. Pattie Jr. et al., Science 360, 627 (2018). Thanks: Chen ‐ Yu Liu 30
Moving forward Projected statistical uncertainty: 0.15 s Last beam cycle (2017 ‐ 2018): systematic uncertainty: 0.10 s total uncertainty: 0.18 s Achievable over the next 2-3 years. Store for 1.5 hour 31
Neutron beta decay 32 Thanks: Albert Young Outlook for precision beta ‐ decay experiments
Neutron beta decay 33 Thanks: Albert Young Outlook for precision beta ‐ decay experiments
Neutron lifetime, beta asymmetry and 0 + 0 + nuclear 34 From UCNA Phys. Rev. C 97 , 035505 (2018) Outlook for precision beta ‐ decay experiments
Neutron beta decay: ‐ 35 Thanks: Fred Wietfeldt Outlook for precision beta ‐ decay experiments
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