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Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances Jefferson Lab and the N* programme at CLAS Hyperon results and status of N* The future The Jefferson Lab 12GeV upgrade Future facilities – EIC, ESS, ELI SCAPA
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Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Apr 01, 2015

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Page 1: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Missing Resonances and BeyondKen Livingston, University of Glasgow, Scotland

Nucleon resonances and complete measurements

Missing nucleon resonances

Jefferson Lab and the N* programme at CLAS

Hyperon results and status of N*

The future

The Jefferson Lab 12GeV upgrade

Future facilities – EIC, ESS, ELI

SCAPA

Page 2: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Clear indication of resonances

Broad and overlapping

Below energy regime of PQCD

Constituent quark models SU(6) x O(3)

Eg. Forsyth & Cutkosky, Koniuk & Isgur,

Capstick & Roberts

Missing resonances

γp cross section: World Data

Most data is from πN scattering and single π photoproduction.

Cross sections are not enough – need angular distributions and polarization observables.

Hyperons (nucleons with strange quark) are promising ( + -> g N + and g + -> N + )

With D13

Without D13

Mart & Benhold, Phys. Rev. C 61 012201(R) (1999)

Constituent quark models predict many resonances, but several missing.

Are they wrongly predicted, or difficult to find experimentally?

Page 3: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Polarization observables in pseudoscalar (0-) meson production

4 Complex amplitudes: 16 real polarization observables.

Complete, model independent, measurement from 8 carefully chosen observables.

I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95 347 (1975).

πN: high statistics KY recoil: self-analysing

( )

Systematics of detector acceptance cancel out.

Only need to know Plin, the degree of linear polarization.

Page 4: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

A B C

Continuous Electron Beam Accelerator Facility

® E: 0.75 –6 GeV® Imax: 200mA® RF: 1499 MHz® Duty Cycle: 100%® s(E)/E: 2.5x10-5

® Polarization: 80%® Simultaneous

distribution to 3 experimental Halls

Injector

LIN

AC L

INA

CExperimental Halls

Jefferson Lab, Virginia, USA

TAGGER

Page 5: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

CEBAF Large Acceptance Spectrometer

Cherenkov Counter e/ separation, 256 PMTsTime of Flight

Plastic Scintillator, 684 PMTs

Drift Chamber35,000 cells

Target + start counter e mini-torus

Electromagnetic Calorimeterlead/plastic scintillator, 1296 PMTs

Torus Magnet6 Superconductive Coils

Page 6: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Ee

Ee’

Eg = Ee - Ee’

11m

Amorphous radiatorDiamond radiator

up to 90% linear polarization

Ee

Diamonds

Need to be “perfect” monocrystals

Assessment difficult and expensive

Tagger in Intregrating mode

…. Could we do this at SCAPA?

Hall B Photon Tagger and Coherent Bremsstrahlung

Page 7: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Polarization observables at CLAS

+ N → m

Linear Polarisation

Circular polarisation

Nucleon recoil polarimiter x → Y

Hyperons are “self analysing”

Transverse polarized nucleon targets p n

Longitudinally polarized nucleon targets p n

Crystal Ball MAMI,D.Watts, Edinburgh.

Page 8: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

L S0

Single polarization observables S Photon asymmetry

P Recoil polarization (induced pol. along y)T Target asymmetry

Double polarization observablesOx Polarization transfer along xOz Polarization transfer along z

Polarization observables in g + p → K + Y (Lin Pol Beam, LH2 target)Craig Paterson, Glasgow

Page 9: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Polarization observables in g + p → K + Y (Lin Pol Beam, LH2 target)Craig Paterson, Glasgow

Good agreement with previous data.Better statisticsMany more bins in CM angle and Energy.

Ph

oto

n A

sym

met

ry g

+ p

→ K

+ L

D

ou

ble

Po

l O

bs

Cx

fo

r g

+ p

→ K

+ L

Gent Regge + Resonance Model(Corthals et al. Phys Rev C73 2006)

Data +Regge background (R) - - - - - - - - -R + core resonances (C) - . - . - . - . -R + C + D13(1900) __________R + C + P11(1900) __ __ __ __

Cos (θcm) K

Page 10: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

• Detect p- n, K+

• Σ from p- n inv. mass

Sergio Anefalos Pereira, INFN. Phys. Lett. B 688 (2010) 289-293

• CLAS Data ▲ LEPS _____ Gent RPR model

Edwin Munevar, GWU

PREL

IMIN

AR

Y

Polarization observables in g + n → K + Y (Lin Pol Beam, LD2 target)

gn (p) -> K0s L0 (p)

gn (p) -> K0s S0 (p)

1st measurements, S P, T, Ox,Oz

PREL

IMIN

AR

Y

Neil Hassall, Glasgow

Page 11: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Status of N* program - complete measurements

✔ - published, ✔ - acquired, ✔ - running now

Each ✔ ✔ represents a future publication.

σ Σ T P E F G H Tx Tz Lx Lz Ox Oz Cx Cz

Proton target

pπ0 ✔ ✓ ✓ ✓ ✓ ✓ ✓

nπ+ ✔ ✓ ✓ ✓ ✓ ✓ ✓

pη ✔ ✓ ✓ ✓ ✓ ✓ ✓

pη’ ✔ ✓ ✓ ✓ ✓ ✓ ✓

pω ✔ ✓ ✓ ✓ ✓ ✓ ✓

K+Λ ✔ ✓ ✓ ✔ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✔ ✔

K+Σ0 ✔ ✓ ✓ ✔ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✔ ✔

K0*Σ+ ✔ ✓ ✓ ✓

Neutron target

pπ- ✔ ✓ ✓ ✓ ✓ ✓ ✓

pρ- ✓ ✓ ✓ ✓ ✓ ✓ ✓

K-Σ+ ✓ ✓ ✓ ✓ ✓ ✓ ✓

K0Λ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

K0Σ0 ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

K0*Σ0 ✓ ✓

PhD awarded - S. Fegan FROST2 new students – HDIce (running now)

Page 12: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

• Spin density matrix elements in bins ΔW = 10 MeV, for W = 1.7–2.4 GeV in blue - blue shades.

• Previous world data in red.

Search for baryon states in γp pω pπ➝ ➝ +π-(π0)

M. Williams, et al. (CLAS) , Phys.Rev.C80:065208,2009

M. Williams, et al. (CLAS) , Phys.Rev.C80:065209,2009

F15(2000)/G17(2190)

ω production is dominated by the well known F15(1680), D13(1700) and G17(2190), and a predicted “missing” F15(2000).

Status of N* program

Page 13: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

The JLab 12GeV upgrade (15min)

CHL-2

Upgrade of the arc magnets

Construction of the new Hall D

Beam Power: 1MWBeam Current: 90 µAMax Pass energy: 2.2 GeVMax Enery Hall A-C: 10.9 GeVMax Energy Hall D: 12 GeV

Upgrade of the instrumentation of the existing Halls

Page 14: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

< 6 GeV

Spectroscopy with CLAS12

Low Q Tagging Facility or Forward Tagger

Electron scattering at “0” degrees (LowQ, post-target tagging): low Q2 virtual photon real photon

Photons tagged by detecting the scattered electron

Quasi-real photons are linearly polarized and the polarization can be determined event by event

Highly segmented calorimiter BGO

Opportunity to test / develop at SCAPA?

Hadron spectroscopyHeavy mass baryon resonances (Cascades and -)

Meson spectroscopyH target and search for exotics4He and other gas targets

Focus on Generalized Parton Distributions

Page 15: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

GlueX: Confinement and the search for QCD exotics

Simplest quark-structure is a meson

Confinement: Quarks cannot exist alone

+ =(, K) JPC = 1-- , 1++

Hybrid Mesonor , , , … ?

+ =(, ) JPC = 0-+, 1-+, 2-+

0+-, 1+-, 2+-

Exotic!

Flux

tube

forms

between

qq

Use a real photon beam

Excite the glue:Study hybrid mesons

G. Bali

Page 16: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

GlueX: Confinement and the search for QCD exotics

Glasgow:Diamond selectionCoherent bremsstrahlungPolarimetry SCAPA ?

Page 17: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Wider context

20162012

MAX IV

EIC ?USA

Sweden

Romania

Germany

Sweden

Scotland SCAPA

2020

Long standing Glasgow

collaborations

Page 18: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

SCAPAScottish Centre for the Application of Plasma-based Accelerators

“Harnessing plasma waves as radiation and particle sources” Dino Jaroszynski

Laser Wakefield Acceleration

Ultra-short, ultra-intense laser pulses from commercially available table-top terawatt femtosecond lasers. Electron bunches:Mean energy above 1 GeV, an energy spread of about 1% and a peak current exceeding 1 kA.

Protons: Yes please

Page 19: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

0.1 – 1 GeV

g = 200 - 2000

plasma filled

capillary

undulator

1 J 40 fs 800 nm

wakefield accelerator

6.5 MeV photo-injector

laser

optical self-injection

SCAPAALPHA-X running now

~20fs

Diamond

Many of these make this

SCAPA needs the expertise of nuclear physicists …. today!

Beam characterizationWe already do this: Nature Physics 7, 867–871 (2011) D.Hamilton ++Polarimetry

Spectrometers and beam conditioning

Detectors

Data Acquisition / analysis

SImluation

Providing expertise opens many doors

EDUCATION EDUCATION EDUCATION

Undergraduates

PhD students

Young postdocs.

Opportunities for nuclear physicists

Detector developmentRF PMTs, GEMs, Diamond detectors

DiamondsQuality assessment, channeling radiation, polarimetry

Fundamentsl Hadron and Nuclear Physics Lifetime measurements The unknown, open doors to ESS, ELI

Compact Muon Source (next slide)

RF PMTs (J.Annand, Glasgow + Yerevan)ps timing resolution500MHz rate capability

Page 20: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

500L

Compact Muon Source at SCAPA

Assay of radioactive waste: Glasgow applied project with NNL

There exists, somewhere, a large stockpile of barrelsof unclassified radioactive waste.

Need to determine the existence of high Z materials.

Scattering of Muons.

Muons from cosmic rays.

Method is very promising.Rate of cosmic muons ~5Hz / m2

Assay will take 10s of years not feasible.

Need a muon beam

Page 21: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

1 GeV

10Hz

Wakefield accelerator

Light solid targetBrem radiator Magnetic element

Simulated using Geant 4 and MAID2007, D. Hamilton, Glasgow

Similar to method used at ISIS

Rate Estimate

Compact muons: ~9kHz / m2

Compared toCosmic muons ~5Hz / m2

Compact Muon Source at SCAPA

Compact, made from “standard components”.

>103 rate increase over cosmics.

Pion beam to do hadron physics (eg pion lifetime measurement with RF PMTs)

Muon beam for materials science.

γn pπ➝ - p- ➝ m- n -m (l = 7.8m)

Page 22: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Summary

Missing Resonances

Lots of progress internationally.

Strangeness very important – 1st complete measurement

Next few years should see definitive results.

Jlab 12

CLAS12 and GlueX Continuing spectroscopy

Heavier baryons

Hybrid mesons

SCAPA

Many new opportunities

Physics

Detector development

Education

Compact muon source

Page 23: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.
Page 24: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

p (n)nRussell Johnstone, Glasgow

K production on n. Deuterium target

PREL

IMIN

ARY

pho

ton

asy

mm

etry

How good a “free” neutron target is Deuterium ?

G13. Compare photon asymmetry of p (n)nwithp (free and bound p)

× Free

● Quasi free

Free and quasi-free protonQuasi free neutron good approx. to free, here.

Coscm (-1.0 - +1.0)Each plot is 200MeV photon energy bin1100-2150MeV

Page 25: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

G13 n (p)s pn (p)s pNeil Hassall, Glasgow

K production on n. Deuterium target

Page 26: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.
Page 27: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.
Page 28: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

• Tagging spectrometer with high rate, good energy and timing resolution

• High precision goniometer (GWU)

• High quality, thin diamond (Glasgow)

• Tight photon beam collimation (ISU)

• Polarimetry

“A device called a goniometer tilts the diamond, much like a lady turning her hand to admire the sparkle of a new ring.” - JLAB On Target Magazine

Peak > 90% pol.

CLAS coherent bremsstrahlung facility

Photo

n

ener

gy

P > 90%

Page 29: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Measurements with photon beam profile detectorD. Glazier, Glasgow

1st Measurement of 2D photon enhancement for coherent bremsstrahlung (MAMI,Mainz) paper in preparation

• Good agreement with coherent bremstrahlung calculations

• Improvements in incoherent component, collimation + multiple scattering.

• No evidence of high energy photons from quasi channeling.

• Investigation of 2D strip detector for polarimetry

Coherent peak at 300Mev, MAMI electron beam energy 855MeV

below peak coherent peak above peak

Page 30: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Photon Asymmetry, , extracted from cos(2) fit to azimuthal kaon distribution

Fits shown for 1 energy bin

340 (20E, 17) kinematic bins

Almost full angular coverage

g8b preliminary results -

Page 31: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

g8b preliminary results -

Results compared with previous results from GRAAL7, 50MeV Energy bins

1175 -> 1475MeV

Good agreement with previous results

PREL

IMIN

AR

Y

Page 32: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Results compared with previous results from LEPS6, 100MeV Energy bins

1550 -> 2050MeV

More bins for our data!!!

Increase the angular coverage to backward angles

PREL

IMIN

AR

Y

g8b preliminary results -

Page 33: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.
Page 34: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Use reaction with a known photon asymmetry

• Can be high statistics

• Very good relative monitor of polarization

• Combined beam, target polarization.

• Non-indpendent – depends on specific expt

• Need very good systematics or calibration

• Awaiting MAMI polarized target and polarised photon beam in 2nd half of 2007

Polarimetry: from hadronic reactionR. Beck, Mainz -> Bonn

Recent preliminary results from JLab (g8b)

• Proton target

• Back to back charge particles in Start Counter

• Atomic or hardonic ?

• Asymmetry from ~20mins DAQ data

• Constant with E from 1.3GeV – 1.9GeV

Page 35: Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland Nucleon resonances and complete measurements Missing nucleon resonances.

Resonances

Pythagoras (c. 500 B.C.)Notes on a string which sound harmonious have simple ratios.

1st Resonance modelCreated a system for tuning instruments The 1st musical scale

… and then the universe

Music of the SpheresIf there is insufficient data even the wackiest of models cannot be ruled out.