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 neutron stars
A new method for extracting nucleon 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 quark model with confinement and one gluon 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 quark model 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 Proton - 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, Hadron 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 Deuterium photodisintegration with linearly polarised photons
!" − !∥ = '()*+,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
electrons,muons, D –> Free fermi gas
d*(2380) –> Free boson 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 neutron star mass around 2M◎ Composition – “Standard” with d*(2380)
1 n
10-1 p
e-
- 10-2 µ Particle 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 protons/neutrons • Can we see it in nuclei ?? Compton scattering from in medium nucleons? 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 matter 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? Pions, Kaons, Delta ? Hyperons ? Light quarks Baryons 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