UK Hadron Physics

D. G. Ireland

10 October 2014 NuPECC Meeting, Edinburgh

2

Nuclear Physics Landscape

3

Key Physics Questions

Generation of MassConfinement

Nucleon Spin

4

Which facilities are used?

GlasgowEdinburgh

MAX-Lab, Lund

Mainz

Jefferson Lab

5

Jefferson Lab (and 12 GeV Upgrade)

8 January 2014

New Hall

Add arc

Enhanced capabilitiesin existing Halls

Add 5 cryomodules

Add 5 cryomodules

20 cryomodules

20 cryomodules

Upgrade arc magnets and supplies

CHL upgrade

The completion of the 12 GeV Upgrade of CEBAF was ranked the highest priority in the 2007 NSAC Long Range Plan. Scope of the project includes:

• Doubling the accelerator beam energy• New experimental Hall and beamline• Upgrades to existing Experimental

Halls

6

JLab - Hall A

High Resolution Spectrometers,plus BigBite

7

JLab - Hall A Upgrade

High Resolution Spectrometers,plus BigBite

plus Super Bigbite Spectrometer (SBS)

JLab – Hall B

8

JLab – Hall B Upgrade

9

CLAS12

Forward Tagger

10

The MAMI Facility

• 100% duty factor electron microtron

• MAMI-C 1.5 GeV upgrade

(MAMI-B 0.85 GeV)

One of the MAMI-C magnets

e

11

Crystal Ball at MAMI

g

DE g ~ 2 MeV108 g sec-1

12

Nucleon Structure

13

Reactions

Elastic Scattering

Semi-Inclusive Deep Inelastic Scattering (SIDIS)

Deeply Virtual ComptonScattering (DVCS)

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Nucleon Form Factors

Q2=q2-n2

15

Quark Distributions

JLab Upgrade 15

Projected SBS/BB data 11 GeV 8.8 GeV 6.6 GeV

16

Baryon Resonances

Quark Model N* Resonances

Lattice QCD

Quark Model D* Resonances

17

CLAS results γp→K+Λ → K+pπ-

Bonn-Gatchina Coupled Channel Analysis, A.V. Anisovich et al, EPJ A48, 15 (2012)

(Includes nearly all new photoproduction data)

M. Mc Cracken et al. (CLAS), Phys. Rev. C 81, 025201, 2010 R. Bradford et al. (CLAS), Phys.Rev. C75, 035205, 2007

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Evidence for new N* states and couplings

19

Coherent Pion Photoproduction

Angular distribution of p0 → PWIA contains the matter form factor

p0 final state interactions - use latest complex optical potentials tuned to p-A scattering data. Corrections modest at low pion momenta

Photon probe Interaction well understood p0 meson – produced with

~equal probability on protons AND neutrons.

Reconstruct p0

from p0→2 g decay

ds/d (W PWIA) = (s/mN2) A2 (qp*/2kg) F2(Eg

*,qp*)2 |F

m(q)|2 sin2qp

*

20

208Pb neutron skin

21

Comparison with previous measurements

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

2

4

6

8

10

12

14

Pion scattering

PREX

Drnp

Proton scattering

Antiprotonic atomsHeavy ion diffusionElectric dipolePygmy dipole

}Coherent pion

DropletNstar + QMC

Latimer

Tsang

Analyses using theory, expt, observation.

22

Future directions

23

Structure Functions

k y

kx

-0.5

0.5

0.0

-0.5 0.0 0.5

bx [fm] Anselmino et al., 2009QCDSF/UKQCD

Coll., 2006

2+1 D picture in momentum space2+1 D picture in impact-parameter space

TMDsGPDs

• Accessed through Semi-Inclusive DIS

• OAM through spin-orbit correlations?

• Accessed through exclusive processes

• Ji sum rule for nucleon spinF

1T┴(x

) [

Siv

ers

fun

ctio

n]

quark density

Lattice QCD

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Future directions… Hadron Spectroscopy

• Exotic mesons

• Very strange baryons

25

The Search for “Dark Photons”

26

Sea quarks and the glue that binds us all

Proton parton density functions

(PDFs)

27

Electron-Ion Collider Designs

Stage I Stage II eRHIC @ BNL

MEIC / EIC @ JLab √s = 13 – 70 GeV

Ee = 3 – 12 GeV

Ep = 15 – 100 GeV

EPb

= up to 40 GeV/A

√s = 34 – 71 GeV

Ee = 3 – 5 (10 ?) GeV

Ep = 100 – 255 GeV

EPb

= up to 100 GeV/A

√s = up to ~180 GeV

Ee = up to ~30 GeV

Ep = up to 275 GeV

EPb

= up to 110 GeV/A

√s = up to ~140 GeV

Ee = up to 20 GeV

Ep = up to at least 250 GeV

EPb

= up to at least 100 GeV/A

(EIC)(MEIC)

28

Summary

GlasgowEdinburgh

MAX-Lab, Lund

Mainz

Jefferson Lab

29