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

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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.

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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.”

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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

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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

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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) ) )

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Michael Ramsey-Musolf slide on C Michael Ramsey-Musolf slide on C violation with P conservationviolation with P conservation

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3434

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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.

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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))

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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

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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

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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