Recent results for EM coupling of d*(2380) (& a speculative aside)

Dan Watts University of York Outline

d*(2380) – a multiquark state ? • Evidence for the d*(2380) • First calculation of potential impact on stars

A new method for extracting momentum distributions? pn scattering with large acceptance

• pn ® d* ® DD ® dpp — pn ® d* ® DD ® NNpp π p Δ π p Δ N d N n Δ π n Δ π

— pn ® d* ® pn p p

n n d* evidence in p-n scattering pnèdp±p± PLB 721 (2013) 229

pnèdp0p0 p+p0 PRL 106 (2011) p+p- 242302

WASA data

PRL 112 (2014) 202301 pnèpn PRC 90, (2014) 035204 pn ® d*(2380) I(Jp) = 0(3+)

pnèppp-p0 pnèpnp0p0 pnèpnp+p-

d* d* d*

PRC 88 (2013) 055208 PLB 743 (2015) 325 PWA including new polarized np data

PRL 112, 202301, (2014) PRC 90, 035204 , (2014)

Strong resonance 3 signature for d* in D3 wave

I(Jp) = 0(3+) d*(2380)

Gives an explanation for (previous) inability for old PWA to describe total new np cross section !

DD decay ~ 90% pn decay ~10% (ang. mom. barrier, double spin-flip) What is the d* - Hexaquark ?

u Any model with confinement and one exchange inevitably predicts a d* with (I)JP=(0)3+ ~1.2 fm T Goldman et. al. Phys. Rev. C 39, 1889 (1989)

Recent microscopic CC chiral DD + hidden colour F. Huang et al, Chin.Phys. C39 (2015) 7, 071001

Does the d* have EM coupling – ~0.7 fm can we measure it’s size ?? gdèdp0p0 Photoproduction of the d*

SPRING8 First measurement of final CB@MAMI state neutron polarisation

Neutron - N* (CB@MAMI) !∗ NPA 933 (2015) 104 g+d ® d*(2380) p + I(J ) = 0(3 ) gdèpn

CB@MAMI

Legendre polynomial Analysis of s, S

# $ % $ + ~ ∑)*+ ,)-) (/012) %& d* search in dominant Δ π decay channel d* d π g +d -> dp0p0 - (equivalent of pn-> dp0p0) Δ

CB@MAMI (Guenther et, al, 2017) SPRING8 (Ishikawa et. al. PLB 772 (2017) 398)

N*->dp0p0 background Egorov, Fix, NPA933 (2015) 104-113) d* (with established M and G) M~2380 MeV G~70 MeV

Accurate data in region of d* -> need detection low TD

-> active deuteron target photodisintegration with linearly polarised

!" − !∥ = '()*+,2. !" + !∥

4 Σ~ ∑234 52'2 (*+,Θ)

Bashkanov, DPW, Kay, CB@MAMI; PLB789 (2019) 7-12 Deuterium photodisintegration with linearly polarised photons

& E2 Σ~ ∑$%& '$($ (*+,Θ) H.Ikeda et al.,NPB172,509,(1980)

E2 transition Þ small M3 transition Þ dominant

M3 /012324514 6347 8∗ :;<= as a compact object

Bashkanov, DPW, Kay, CB@MAMI; PLB789 (2019) 7-12 Large acceptance nucleon polarimeter at MAMI

Experimental beamtime - late 2016

Radius of Point of Closest Approach as Function of Z 200 ScatterVertexZr_Buffer XY Vertex Point of Scatter from DOCA Method 300 80 ScatterVertexXY_Buffer Entries 127025 60 MeanEntries x 319271-1.752 180 60 Mean y -3.392 RMS x 38.09 RMS y 50 40 38.66

160 20 40 250

0 30

-20 140 20 -40 10 200 Polarimeter -60 120 0 Y reactionvertexY (mm) -80 -80 -60 -40 -20 0 20 X40 reaction60 vertex80 (mm) 100 150 ) scatter vertex (mm) vertex ) scatter

Radius/mm 80

n,p 100 60 Target

40 cell 50 20

Radius of ( 0 0 -200 -150 -100 -50 0 50 100 150 200 Z/mm Z reaction vertex (mm) Induced nucleon polarisation (P)

First detailed measurement of final state neutron polarization in D(g,pn)

D(g,pn) ⚈ neutron (CB@MAMI preliminary) o ⚈ proton (Ikeda et al, PRL 42 1979) qcm=90

Conventional background, (Kang et al)

qcm

Bashkanov, DPW, Kay, CB@MAMI; in preparation q q q Cx'(Eg) CM 0 - 36 Cx'(Eg) CM 36 - 72 Cx'(Eg) CM 72 - 108 2 2 2 1.5 1.5 1.5 1 1 1 0.5 0.5 0.5

Transferred polarisationx' (C ) x' x' 0 x 0 0 C C C -0.5 -0.5 -0.5 Early stage results – polarization transfer circ polarized g to neutron -1 -1 -1 Next stage – include analyzing power-1.5 -> Cx -1.5 -1.5 -2 -2 -2 200 300 400 500 600 700 800 9001000 200 300 400 500 600 700 800 9001000 200 300 400 500 600 700 800 9001000 Eg Eg Eg q q q Cx'(E ) qCM 108 - 144 Cx'(E ) qCM 144 - 180 Cx'(Eg) CM 0 - 36 Cx'(Eg) CM 36 - 72 Cx'(Eg) CM 72 - 108 g g 2 2 2 2 2 D(g,pn) 1.5 1.5 1.5 1.5 1.5 q =125o 1 1 1 1 cm 1 Fixed p = 0 0.5 0.5 0.5 0.5 0.5 y x' x' x' 0 x' 0 x' 0 0 0 C C C C C Fixed p (arbitrary scale) (arbitrary (arbitrary scale) (arbitrary x y

-0.5 -0.5 -0.5 -x 0.5 -0.5 C C -1 -1 -1 D(g,pn) -1 -1 Variable p o y -1.5 -1.5 -1.5 qcm=90 -1.5 -1.5 -2 -2 -2 -2 -2 200 300 400 500 600E 700 800 9001000 200 300 400 500 600E 700 800 9001000 200 300 400 500 600E 700 800 9001000 200 300 400 500 600 700 800 9001000 200 300 400 500 600 700 800 9001000 g g g Eg Eg

Cx'(E ) qCM 108 - 144 Cx'(E ) qCM 144 - 180 2 g 2 g 1.5 1.5 1 1 Fixed p = 0 0.5 0.5 y x' 0 x' 0 C C Fixed p -0.5 -0.5 y -1 -1 Variable p -1.5 -1.5 y -2 -2 200 300 400 500 600 700 800 9001000 200 300 400 500 600 700 800 9001000 Eg Eg The d*(2380) in neutron stars ?

Neutron star model:

Nucleons –> Relativistic mean field (GM1) –> Compatible with recent GW data

,, D –> Free fermi gas

d*(2380) –> Free gas

Tolmann–Oppenheimer–Volkoff equations -> hydrostatic equilibrium with GR d*(2380) – influence on the EoS

d*(2380) -> Higher energy densities achieved with lower pressure (Bosonic!) -> Abrupt cutoff in maximum mass around 2M◎ Composition – “Standard” with d*(2380)

1 n

10-1 p

e-

- 10-2 µ fraction

d*(2380) Glendenning-3 -Moszkowsk 10 02468 Density ρ/ρ 0 1 n (a)

10-1 p

e-

- 10-2 µ Particle fraction

d*(2380) -3 10 02468 Composition – “Standard”Density with ρ D/ρquartet and d*(2380) 0

1 n (b)

10−1 p

e-

- 10−2 µ - 0 + ++ Particle fraction ∆ ∆Vidana∆, Bashkanov∆ , DPW, Pastore arxiv 1706.90701 (2017) d*(2380) Phys. Lett. B , **, 2018 Glendenning−3 -Moszkowsk 10 02468 Density ρ/ρ 0 Recent running @ MAMI

Experiment carried out in Feb 19

Target Diameter mass Beamtime (hours) 48Ca 10mm 502.6 180 40Ca 10mm 503.2 120 112Sn 20mm 3800 54

Relativistic DFT 0.22(2) fm

Target holder and plug Targets contributed by GSI 48Ca(g,p0) @ MAMI

Analysis at very early stage -> Cannot draw physics conclusions but can see data quality

40

b/sr] Ca -: Eg = 190-200 MeV 20 3 3.73 (MeV) 40 µ Ca [ 48

W 18 Ca 48

/d Ca s 16 d units) 102 ~1/2 of data available 14 2+:3.83 (MeV)

Counts [arb. units] 12 Coincident

arbritary 10 ( nuclear decay W 8 d / photons

s 6

d 10 4

2

0 0 2 4 6 8 10 12 0 20 40 60 80 100 120 140 160 180 energy of gamma [MeV] qp0 [deg]

40

b/sr] Eg = 190-200 MeV Ca µ [ 102 48 W Ca /d s d 10 !!! Caveats !!!

1 Calibrations not complete, incoherent backgrounds/empty target -1 10 not removed, detector acceptance crudely incorporated, …

10-2 0 20 40 60 80 100 120 140 160 180

qp0 [deg] In medium nucleon Compton scattering

• Favourable entrance and exit probe (ISI/FSI negligible) • Amplitude ~identical / • Can we see it in nuclei ?? Compton scattering from in medium ? 40Ca 48Ca p (Eg: [350.000,400.000]) p (Eg: [350.000,400.000]) A-1 A-1 p_recoil_Eg_5 clone_5 2 Entries 2308736 Entries 916

Mean 244.9 Mean 563.7 1.8 40 Std Dev 166.1 Std Dev 259.6

Ca Ca-48 / Ca-40 48 40 1.6 102 Ca/ Ca Counts [arb. units] 48Ca 1.4

1.2 10 1 ProjectionX of biny=[6,55] [y=10.0..110.0]

slice_px_of_p_recoil_vs_me_Eg_6

Entries 1607 Mean 82.28 0.06 Std Dev 66.62 0.8 PA-1 < 150 MeV/C 0.05 1 0.6 48 0.04 E =375 MeV Number of Entries Ca g Missing energy<30 MeV 0.4 0.03

10-1 0.2 0.02

0 0.01 100 200 300 400 500 600 700 800 900 100 200 300 400 500 600 700 800 900 1000 p [MeV] p [MeV] p (Eg: [450.000,500.000])A-1 p (Eg: [450.000,500.000])A-1 0 A-1 A-1 p_recoil_Eg_7 clone_7 -100 -50 0 50 100 150 200 2 missing energy [MeV] Entries 674894 Entries 136

Mean 198.6 Mean 578.2 40 1.8 Ca Std Dev 131 Std Dev 255.4

10 Ca-48 / Ca-40 48 40 48 1.6 Ca/ Ca Counts [arb. units] Ca

1.4

1 1.2

1

10-1 0.8

0.6 Eg=475 MeV Missing energy<30 MeV 0.4 10-2

0.2

0 100 200 300 400 500 600 700 800 900 100 200 300 400 500 600 700 800 900 1000 p [MeV] p [MeV] A-1 A-1 Compton scattering from in medium nucleons? 40Ca 48Ca p (Eg: [400.000,450.000]) p (Eg: [400.000,450.000]) A-1 A-1 p_recoil_Eg_6 clone_6 2 Entries 7659037 Entries 7285

Mean 248.5 Mean 522.4 1.8 Std Dev 165.8 Std Dev 286.8 102 Ca-48 / Ca-40 40 1.6 Counts [arb. units] Ca 48Ca/40Ca 48 Ca 1.4

1.2 10

1

ProjectionX of biny=[6,55] [y=10.0..110.0]

slice_px_of_p_recoil_vs_me_Eg_6 Entries 1607 0.8 Mean 82.28 0.06 Std Dev 66.62

PA-1 < 150 MeV/C 0.6 0.05 1

48 0.4 0.04 Number of Entries Ca Eg=375 MeV Missing energy<100 MeV 0.03 0.2

0.02 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 p [MeV] p [MeV] 0.01 A-1 A-1 p (Eg: [450.000,500.000]) p (Eg: [450.000,500.000]) A-1 A-1 0 p_recoil_Eg_7 clone_7 2 -100 -50 0 50 100 150 200 Entries 4406333 Entries 7644 missing energy [MeV] Mean 237.4 Mean 551.6 1.8 2 40 161.8 260.4 10 Ca Std Dev Std Dev Ca-48 / Ca-40 1.6 48 40 Counts [arb. units] 48Ca Ca/ Ca 1.4

1.2 10

1

0.8

0.6 1 Eg=475 MeV Missing energy<100 MeV 0.4

0.2

0 100 200 300 400 500 600 700 800 900 100 200 300 400 500 600 700 800 900 1000 p [MeV] p [MeV] A-1 A-1 Compton scattering from in medium nucleons? p vs. missing energy (Eg: [400.000,450.000]) A-1 p_recoil_vs_me_Eg_6 1000 Entries 1.327466e+08 Mean x 109.4

[MeV] 900 Mean y 215.1 A-1 p Std Dev x 63.25 800 10-2 Std Dev y 185 E =425 MeV 700 g

600

500 -3 10 400

300

200 10-4 100

0 -100 -50 0 50 100 150p vs. missing200 energy (Eg: [400.000,450.000]) A-1 p_recoil_vs_me_Eg_6 Entries 1.327466e+08 Mean x 130.2

Mean y 451.2 1000missing energy [MeV] Std Dev x 52.25 Std Dev y 142.2

[MeV] 900 A-1 p

-4 800 10

700

600 -5 10

500

400

-6 10 300 -100 -50 0 50 100 150 200 missing energy [MeV] Summary

EM probes -> helping to elucidate the detailed physics of strongly interacting and nuclei

Ongoing programme will provide valuable data to constrain the nucleonic (and non-nucleonic) contributions to the equation of state

Hadron & medical physics group at York

Dr

Dr Mikhail Baskanov Dr Nick Zachariou Dr Dominik Werthmueller Dr Jamie Brown Dr Julien Bordes Rutherford fellow Rutherford fellow PDRA PDRA (medical) PDRA (medical) Large acceptance nucleonSikora polarimeter, DPW, Glazier et. al. PRL112 022501 (2014)

MWPC Lightguides

PMTs

PID III Liquid deuterium cell Graphite

n(q,f) =no(q){1+A(q)[Pycos(f)–Pxsin(f)]

Analysing power Number of nucleons of scatterer scattered In the Polar angle distribution x and y (transverse) components direction q, f for unpolarised nucleons of nucleon polarisation Hadronic matter at high density

Neutron skins -> experimental constraint on nucleonic based matter

At higher densities (>2-3ro): our understanding of strongly interacting matter is still evolving –> better nuclear data

Nucleons d*(2380) ??

Mesons ? Plasma? , , Delta ? ? Light with one (or more) Spin flip strange quarks L, S, X What is the d* - Deltaron hypothesis

I(Jp) = 0(1+) I(Jp) = 0(3+)

u u u d d d u u u d d d

Threshold

2.2 MeV r ~ 4fm p n 80 MeV

deuteron d* Δ Δ

But width of d* is 70 MeV – width(DD)~240 MeV? r ~ 1.2fm & strong decay open (NNpp, NDp) ?

EDPOL2

Upstream view Downstream view Neutron !" on Carbon

31 !∗(2380) internal structure

Hexaquark ≈ 66% ΔΔ -./012/0 ≈ 33%

0.7 fm 0.9 fm

95% 5% L=0 Δ Δ Δ Δ L=2 32 !" → "∗ → %& Conventional background '(!" → %&)~810 '(!" → "∗ 2380 → %&)~10&0

' !" → %& ~1000 ' !" → "∗ 2380 → %& BUT

Polarization observables

Federico Ronchetti arXiv 1301.5886 33 d*(2380) SU(3) multiplet

DD !∗(2380)

∗ ∗ ∗ ∗ 01 − 02 + 04 < 016 ≤ 02 + 04

∗ DS* !)(2.53 − 2.60)

∗ DX* !))(2.68 − 2.76)

∗ DW !)))(2.82 − 2.90)

34 Strange Dibaryon decays Isospin %& 10 ∗ d* DD # (2380) DS* ΔΔ → ))**

Strangeness S*S*+DX* X*S*+DW )Λ ∗ #+(2530-2600) ΔΣ∗ → ()*)(Λ*) → ))***

Strange Dibaryon decays $Λ ∗ !"(2530-2600) ΔΣ∗ → ($*)(Λ*) → $$*** . ∗ . 1 1 2 ,! → - + !" → - + 00* * * Δ2Σ∗2 2 1 Λ* 0* 0*1

. ∗ . ,! → - + !" → - + Λ3