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Update on JEF project Update on JEF project
Liping GanLiping Gan
(On behalf of JEF working group)(On behalf of JEF working group)
Where we are now? Where we are now?
Outcome from the eta physics workshop at ACFIOutcome from the eta physics workshop at ACFI
Plan for PAC42 and beyondPlan for PAC42 and beyond
OutlineOutline
11
Proposal to PAC40 in 2013Proposal to PAC40 in 2013
Perform a simultaneous measurement of η decays to all neutral final states:
η→0, measure BR (~4% precision) and Dalitz distribution to determine two O(p6) LEC’s in the chiral Lagrangian.
Improve BR upper limits by 1-2 orders of magnitude for SM forbidden decays:
η →3, η →20, and other C-violating neutral channels offer the best window for direct test of C-violating and P-conserving new physics.
A new measurement on η →30 with a significant different systematics to constrain the light quark mass ratio.
22
33
Projected JEF ResultsProjected JEF Results
Proj. JEFBR
Up
per
Lim
it
BR
Up
per
Lim
it
Jlab PAC40 report on the JEF proposalJlab PAC40 report on the JEF proposal
Feasibility:Feasibility: “ “The proposed measurements appear to be The proposed measurements appear to be
feasible and the experiment is well suited for the feasible and the experiment is well suited for the tagged Hall D photon beam.” tagged Hall D photon beam.”
Issues: Issues:
“ “The PAC recognizes the scientific interest of The PAC recognizes the scientific interest of performing new measurements of rare eta performing new measurements of rare eta decays with improved sensitivity to test the SM. decays with improved sensitivity to test the SM. However, the PAC identified some issues, However, the PAC identified some issues, mainly related to the theoretical implications of mainly related to the theoretical implications of these measurements.”these measurements.”
44
Workshop on “Hadronic Probes of Fundamental Workshop on “Hadronic Probes of Fundamental Symmetries”Symmetries”
March 6-8, 2014, Amherst Center for Fundamental Interactions, University of Massachusetts Amherst
Web site: https://www.physics.umass.edu/acfi/seminars-and-workshops/hadronic-probes-of-fundamental-symmetries
Participants:Participants:
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• Gilberto ColangeloGilberto Colangelo• John DonoghueJohn Donoghue• Barry HolsteinBarry Holstein• Gene GolowichGene Golowich• Michael R-MMichael R-M• Susan GardnerSusan Gardner• Basian KubisBasian Kubis• Johann BijnensJohann Bijnens• Jens ErlerJens Erler• Sean TulinSean Tulin• Jose GoityJose Goity• Students and postdocs from ACFIStudents and postdocs from ACFI
• Andrzej Kupsc• Marc Unverzagt• Eugene Chudakov• Dave Mack• Simon Taylor• Liping Gan• Rory Miskimen• Alexander Somov
66
1. What is the physics impact of prospective JEF 𝜂→π0γγ measurement?
Probe interplay of VMD & scalar resonances in ChPT an unique window to test the role of scalar dynamics
Provide a stringent constraint on the dark B-boson in 130-415 MeV range.
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88
99
1010
1111
Projected JEF ResultsProjected JEF Results
Proj. JEF
1212Sean TulinSean Tulin
1313Sean TulinSean TulinarXiv:1402.3620
1414Sean TulinSean Tulin
1515Sean TulinSean Tulin
1616Sean TulinSean Tulin
1717Sean TulinSean Tulin
1818Sean TulinSean Tulin
1919Sean TulinSean Tulin
2 . What is the physics impact of prospective JEF 2 . What is the physics impact of prospective JEF
→𝜂 →𝜂 33ππ m measurement?easurement?
More precise value for quark mass ratio ( ): More precise value for quark mass ratio ( ):
fundamental parameters of SM that can be determinedfundamental parameters of SM that can be determined
Have a wide-range impact. Have a wide-range impact.
Example: improve the extraction of VExample: improve the extraction of Vusus from from
Improved VImproved Vusus would then lead to improved tests of CKM would then lead to improved tests of CKM
unitarity:unitarity:
Global context as cross check on systematicsGlobal context as cross check on systematics
Suggest to consider the charged pion final state as wellSuggest to consider the charged pion final state as well2020
Q2=ms
2−m2
md2−mu
2
0K l
2 2 2
ud us ubV + V + V =1
2121
2222
2323
Uncertainties in quark mass ratioUncertainties in quark mass ratio
2424
2525
2626Emilie PassemarEmilie Passemar
2727Emilie PassemarEmilie Passemar
2828
2929
3. What are the possible new opportunities for probing physics beyond the Standard Model (BSM) with low-energy hadronic probes?
C violation with P conservation (CVPC) in eta C violation with P conservation (CVPC) in eta decay BR's could avoid EDM constraints (in a decay BR's could avoid EDM constraints (in a conspiracy scenario which might imply a hidden conspiracy scenario which might imply a hidden symmetry)symmetry)
the theorists are still debating whether effective the theorists are still debating whether effective CVPC ASYMMETRIES in eta decays and neutron CVPC ASYMMETRIES in eta decays and neutron decays are constrained by EDMs at all.decays are constrained by EDMs at all.
3030
3131Michael R-MMichael R-M
((M. Ramsey-Musolf et. al., phys. Rev., D63, 076007 (2001) ) )
3232
Michael Ramsey-Musolf slide on C Michael Ramsey-Musolf slide on C violation with P conservationviolation with P conservation
3333
3434
35
Physics foci Physics foci
η→0: test the role of scalars in ChPT and probe test the role of scalars in ChPT and probe dark B-boson for new physics dark B-boson for new physics
η→30 and η→0+-: constrain the light quark mass ratio (provide an important cross check with significant different systematics on 3 results from European facilities)
C-violating decays (η→3, η→20) and asymmetry in η→0+-: probe C-violating, P-conserving new physics.
3535
Plan for PAC42 and beyondPlan for PAC42 and beyond Get updated proposal ready for June 2 submission Get updated proposal ready for June 2 submission
to PAC42to PAC42
Two new theory focus groups (ChPT and BSM) have formed. They will provide new theory sections to address the issues raised by PAC40. (Due date is the first week of May)
The first draft of proposal will be submit to the collaboration on May 12.
Join the European meson physics network
Keep close collaboration with theorists on the project 3636
The EndThe End
Thanks you!Thanks you!
3737
World Competition in η Decays
3838
JEF at Jlab
Low energy -facilitiesLow energy -facilities
High energy -facilityHigh energy -facility
CBELSA/TAPS at ELSA
e+e-
Collider
Fixed-target
photoproduction
hadroproduction
Filter Background with Filter Background with ηη Energy Boost ( Energy Boost (00))
3939
Major BackgroundMajor Background η →η →00000066 --pp→ → 000 0 ++ neutronneutron
GAMS ExperimentGAMS Experiment
--pp→η→η p ( p ( EE= 30 GeV= 30 GeV ) )
Jlab:Jlab: pp→η→ηpp (E = 9-11.7 GeV)
CB-AGS ExperimentCB-AGS Experiment
--pp→η→η p p ((EE=730 MeV=730 MeV))
η η →→00 00 00
40
Proposed Experiment in Hall D Proposed Experiment in Hall D
Simultaneously measure η neutral decays: η→0, η→3, and …
4040
ηη produced on LH produced on LH22 target with target with 9-11.7 GeV tagged photon beam9-11.7 GeV tagged photon beam: :
γγ+p+p → → ηη+p+p
Reduce non-coplanar backgrounds by by detecting recoil p’sdetecting recoil p’s with GlueX detector with GlueX detector
Upgraded Forward Calorimeter with Upgraded Forward Calorimeter with High resolution, high granularityHigh resolution, high granularity
PbWOPbWO44 ( (FCAL-IIFCAL-II) to detect multi-photons from the ) to detect multi-photons from the ηη decays decays
FCAL
Hadronic Backgrounds Reduction in 4Hadronic Backgrounds Reduction in 4 States States
4141
Event Selection
Elasticity is EL=ΣE/ Etagged-
Energy conservation for γγ+p+p → → ηη+p +p reactionreaction: ΔE=E()+E(p)-E(beam)-M(p)
Co-planarity Δ= ()- (p)
Note: Statistics is normalized to 1 beam day.BG will be further reduced by requiring that only one pair of ’s have the 0
invariant mass.
Signal: 0