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STRANGENESS AND COLD DENSE MATTER
WCU-YITP
Mannque Rho (Saclay & Hanyang) A personal overview: April 21, 2011
STRANGENESS IS “STRANGE”
The strange (s) quark mass is NEITHER too big nor too small. So, one might say the strange quark is BOTH light and heavy!
“Light” → chiral perturbation theory
“Heavy” → Callan-Klebanov kaon-skyrmion bound state hyperon
PDG
Scoccola et al 1989
CK WORKS WELL FOR HYPER-ONS
Wrap “heavy kaon” with a skyrmion
AMBIDEXTERITY OF STRANGE-NESS
“One can go smoothly from `massive’ kaon to `chiral’ kaonin the baryon structure”
Kaplan & Klebanov 1990
RISE AND FALL OF KN SIGMA TERM
A measure of how strangeness enters in nuclearprocesses is in the KN sigma term
Strange quark contributes to the nucleon mass
Old days (pre-lattice): ≈ 350 MeVNow (post-lattice): ≈ 50-60 MeV
Implies the sigma term drops from ∼400 MeV toas low as ∼120 MeV!
dra Dramatic effect?? Talk by H.K. Lee
KAON IN DENSE BARYONIC MATTER
Raging fight/controversy: Kaon is strongly bound vs. weakly bound in nuclear medium
I have no clean argument to rule out one over the other.
What does nature say? According to Gal: Nature is nonlinear!
“STRANGE”PHENOMENON
Kurt Vonnegut, “Cat’s Cradle”
“Strange” things happen with strangeness in densematter in ignorance of what’s really going on in densityat n > n0 .
Alternative scenarios
“Standard” model: Anchored on the Weinberg-Tomozawa term;Coupled channels, unitarity etc.
Kaon bound to skyrmion matter:Anchored on Wess-Zumino anomaly term
NON-STANDARD OBSERVATION
Dense matter simulated with skyrmions on crystalundergoes phase transition from skyrmion matterto half-skyrmion matter, what looks like apseudo-gap phase, at n1/2 > n0 . What’s this in thestandard picture? Georgi’s vector symmetry?
It triggers an additional K-nuclear attraction not seen instandard picture.
Byung-Yoon Park’s talk
APPEARANCE OF FRACTIONIZED SKYRMIONS
skyrmion
half-skyrmion
Simulate dense matter by putting skyrmions in FCC crystals and squeeze them: ½-skyrmions in CC appear at n1/2
B.Y. Park et al,1999
skyrmions Half-skyrmions
ALSO IN HQCD: “DYONIC SALT”
Increasing density
Instantons: FCC
½ instantons(dyons): BCC
Sin, Zahed, R., Phys. Lett. B689, 23 (2010)
Dyons are bound by ~ 180 MeV.
“PHASE”STRUCTURE
Sigma model
HLS model
The ½-skyrmion phase at n n1/2 is characterized by
Rough estimate: n1/2 ~ (1.3 – 2) n0
n1/2ndeconf
i.e. “vector mode”
Is chiral symmetry restored?
No! No-go theorem a la Cohen.
CHARACTER OF ½-SKYRMION PHASE
on the “average” but fp ≠ 0
Nucleon mass scales only slightly
≠ 0
But
Vector meson mass scales
g is the order parameter!
POSSIBILITY FOR EMERGENT PARITY-DOU-BLET STRUCTURE
Dilaton c + HLS+ parity-doublet quasiquarks→ dilaton limit → VM fixed point
Constituent quark mass:
Dilaton limit:
VM fixed point:
Much like the properties of the skyrmion crystal
More on this matter later
Dynamicallygenerated
A la DeTar & Kunihiro 89Jido et al…1998- …
Beane, van Kolck, Weinberg
HY
APPLICATION: STRANGE GOINGS-ON IN COMPRESSED MATTER
Insert anti-kaon in half-skyrmion matter
Skyrmion-1/2-skyrmion background
Ignore kaon back-reaction onto (half-)skyrmion matter
J.I. Kim, B.Y. Park, R. 2009
THERE IS UNEXPECTED(!) ATTRACTION IN ½-SKYRMION MATTER
△B ~ 50-60 MeV
Is this what Akaishiand Yamazaki need for dense kaonic matter ?
Shrinkage?
DB
ANTI-KAON “ROAMING” THROUGH ½-SKYRMION MATTER: WESS-ZUMINO TERM
How to measure isospin spirals?
Monte Carlo simulation
Observation
“Chiral magnetic spirals”
Something similar in Nature
HOW ABOUT ANALOGY TO “MAGNETIC SPI-RALS” WITH SPIN → ISOSPIN?
Pfleiderer & Rosche,Nature, 17 June 2010
Chiral magnetic spiralsDzyaloshinsky-Moriya interaction
TENSOR FORCES ARE DRASTICALLY MODIFIED IN THE ½-SKYRMION PHASE
For density n n1/2 :
n=n0
n=2n0
n=0+p r
Above n1/2, the r tensor gets “killed,” enabling the pions (p0’s) to condense → pionic crystal in dense neutron matter ( e.g., Pandharipande and Smith 74).
Decreasing tensor Increasing tensor
n1/2
For density n < n1/2 :
“standard” nuclear physics
,
Effect on symmetry energy
Scaling prediction
This prediction could be checked or falsified atFAIR or even RIB (e.g., KoRIA) machines
½-skyrmion Scaling prediction
≈
AND AT HIGHER DENSITY?
See “dilaton limit” below!
Do kaons condense In dense matter?
Yes schoolNo school
K-p p
The L(1405) plays an essential role in forming "Kbar Nuclear Clusters" (KNC).
A new window to Nuclear Physics would be opened up through the investigation of KNC.
Experimental information on L(1405) is virtually important to establish the "super-strong nuclear force" (SSNF).
Much ado about (1405) L Y. Akaishi 2010
down
strange
1st generation
strange
2nd generation
uck
Naming by K. Nishijima
wan
The s quark plays a leading rolein forming a dense and cold nucleus.
Strangeness nuclear physics Swan nuclear physicsT. Yamazaki & Y. A.
Ice-9?
K- + p
MeV -27K EMeV 04Γ
1 2 3 r fm0
-50
-200
-300
-400
-500
nuclKU
MeV
L(1405)S+p
L+p
K- + pp
MeV -48K EMeV 61Γ
1 2 3 r fm0
-50
-200
-300
-400
-500
nuclKU
MeV
H2KS+p
L+p
K- + 3He
MeV -108K EMeV 02Γ
1 2 3 r fm0
-50
-200
-300
-400
-500
nuclKU
MeV
H3K
S+p
L+p
Y. Akaishi & T. Yamazaki, Phys. Rev. C 65 (2002) 044005
Shrinkage!
A. Dote et al.Yes, but for skeptics “Ice-9”
8BE 8BEK-
7 fm
Density (/fm^3) 0.0 0.41 0.83
Density (/fm^3) 0.0 0.10 0.20
AntisymmetrizedMolecularDynamics calculation A. Dote, H. Horiuchi, Y. Akaishi & T. Yamazaki, Phys. Lett. B590 (2004) 51.
Dense & Cold
ppnK-
“Challenging problem” !
pp
n
K-
1.5 fm
rN(0) = 9r0
rNav= 3r0
1.2 fm
MeV20,MeV108 E
MeV25,MeV6169 EExp.
DB th -ex ~ 60 MeV
Chiral restoration ?
Relativistic effect ?
Y. Akaishi 2010
“ICE-9”TO SKEPTICS
Ice-nine is a fictional material appearing in Kurt Vonnegut's novel Cat's Cradle. It is supposed to be a more stable polymorph of water than common ice (Ice Ih) which instead of melting at 0 degrees Celsius (32 degrees Fahrenheit), melts at 45.8 °C (114.4 °F).
When ice-nine comes into contact with liquid water below 45.8 °C (which is thus effectively supercooled), it acts as a seed crystal, and causes the solidification of the entire body of water which quickly crystallizes as ice-nine.
Far below L(1405) pole, L(1405) is irrelevant !
One has to start below L(1405) pole !
31
Chang-Hwan Lee
Obscure RGE argument (‘95)by Lee, Sin, R. supports this scenario
But (1405)L is irrelevant for kaon condensation
What does Gal say? No condensation!
Number of kaons
Because of the w repulsion between constituent u quarks in anti-kaons (us).
BUT LATTICE SUGGESTS OTH-ERWISE
Tree-order chiral perturbation calculationreproduces lattice result , which meanshigher-order terms (loops and counter terms)sum to negligible A miracle!!
Detmold et al, 2008
D(ILATONIC)HLS ALSO SAYS OTHERWISE
C. Sasaki, W.-G.Paeng et al 2011
DHLS
HLS is a gauge-equivalent nonlinear sigma model, applicable up to the scale of the vector meson mass ∼ mV ∼ 700-800 MeV and allows chiral perturbation treatment for the case when mV
* /mp becomes ∼ O(1). DHLS takes into account a low-mass scalar degree of
freedom in terms of a dilaton c figuring in the QCD trace anomaly.
Introduce fermionic degrees of freedom in terms of quasi (constituent) quarks or baryons so as to treat dense baryonic matter.
“DILATON LIMIT (DL)”One-loop RGE analysis (W.-G. Paeng et al) indicates thatthere is a “dilaton limit” fixed point approaching the Gell-Mann-Levy-type linear sigma model:
DL fixed point
Consequences
DL fixed point ⇔ VM fixed point?
q
q
q
q
, w r
DL: Suppression of vector exchanges
DL IMPLIES The repulsive interaction between antikaons gets
suppressed as density increases to the dilaton limitThe attractive antikaon-nucleon interactions due to the
exchange of vector mesons ( , )w r get also suppressed.
But the scalar ( (c ) s exchange between nucleon and antikaon with gsqq≈gpqq takes over the attraction lost.
And The famous “hard-core” repulsion in nuclear interactions
should soften at high density. Relevance to 2 solar mass star?
Demorest et al, Nature 467, 1081 (2010)
“All equations of state with kaon condensation, hyperons … other than strongly interacting strange quark matter are ruled out by this star” !!
PSR J1614-2230 (1.97 M⊙)C.-H. Lee’s talk
Ozel, Baym and Guver 2011
Softeningrepulsionhelpful?
Caveat:Lattimer objection
Exotica
nuclearmatter (NM)
NM+kaon condensed (KC)
NM+KC+s quark matter
(K. Kim, H.K. Lee, MR)
3-layer: nuclear-kaon condensed-s-quark matter
H.K. Lee’s talk
END LET US GET STARTED