New States of Strongly Interacting Astrophysical Matter PITP Conference 2005 Mannque Rho (Saclay)

Where does the mass come from? Molecules, Atoms, Nuclei: Masses =sum of masses of constituents + tiny binding energy Constituents: protons, neutrons, electrons Nuclear BE < 1%

Mysteries abound in the Standard Model and Beyond… Where do the quark, lepton etc. masses come from? Where do the quark, lepton etc. masses come from?.. Etc….. Etc… Where do the “dark stuff” in the Universe come from? Where do the “dark stuff” in the Universe come from?.. Etc….. Etc… For someone else!

Mass right around us Proton/Neutron Mass=938/940 MeV Constituents: Quarks and gluons Proton= uud ; Neutron= udd Sum of “current-quark” masses ≈ 10 MeV Where do ~ 99% of the mass come from?

QCD Answer “ Energy stored in the motion of the (nearly) massless quarks and energy in massless gluons that connect them” Proton mass ≈ 1 GeV “Mass without mass” Technically, “chiral symmetry spontaneously broken  SB)” QCD on lattice explains the proton mass within ~ 10%.

Order Parameter Quark condensate: _ ≈ - (0.23±0.03 GeV) 3 → Proton mass ≈ 1 GeV What happens when → 0 ? ≠ 0  S broken = 0  S restored _ _

The Question If the mass is generated by dynamical “dressing,” can it be made to disappear by “undressing” in the laboratories ? Or can one dial the mass to zero? Yes! through dialing the condensate to zero Lattice QCD

(Two) Surprises At High Density (Gravity): Kaon condensation At High Temperature (Heavy-Ion Collisions): Nearly perfect liquid New “unexpected” states are found

Effective Field Theories QCD cannot address directly the problem of going toward the critical point T c /n c, so we need to resort to effective field theories Tools at our disposal: NL  Nonlinear sigma model with pseudo- Goldstone bosons (  K, …) HLS: Hidden local symmetry model with  light vectors (  K *, …)  etc …

In Favor of HLS AdS/QCD indicates a 5-D pure gauge theory giving in 4-D a tower of vector mesons and a multiplet of Goldstone bosons describing QCD in nonperturbative regime Baryons emerge as skyrmions to complete the degrees of freedom required With a suitable truncation and in the chiral limit (quark masses=0), the theory can arrive at the critical point as a fixed point known as “Vector Manifestation (VM)”

Predictions with HLS As → 0, i.e., n (or T)→ n c (or T c ) Theory well defined at this limit!  Hidden gauge coupling g  → 0  Pion decay constant f   F( ) → 0  Even away from the limit, hadron mass (except for  ’s) satisfies “BR scaling”; e.g., in density m(n)/m(0) ≈ f   n)/f   for n ≤ n 0 ≈ g(n)/g(0) for n > n 0 where n 0 = 0.16 fm -3 nuclear matter ¯ ¯ ¯

Nature There are indications that the scaling is operative up to n 0 m   n 0 )/m   ≈ f   n 0 )/f  ≈ 0.8 Bonn: CBELSA/TAPS Collaboration  A→  X→    +X ’ KEK: Deeply bound pionic nuclei

High precision measurements at GSI from 2007

A dense new state above n 0 It is certain that the interior of neutron stars is much denser than nuclear matter: Can one create such a dense system in the laboratories? Answer (T. Yamazaki et al, KEK): Capture anti-strangeness (e.g. K - ) inside nuclei

Mechanism Turns out to be surprisingly simple Huge attraction from two main sources: Attractive K - - nuclear interaction K A   - (1/f      density ≡ - A Density counters E  SB, tending to restore  S  - c  KN  density ≡ - B A+B ~ 200 MeV at n  n 0 =0.16 fm -3

Kaon Potential

Discovery of strangeness nugget A bound pnnK – = “ S 0 (3115)” BE=m p + 2m n + m K – m S =194 ± 5 MeV Average density ~ 3 n 0 KEK 2004 Strong binding overcomes compression energy!

Embed K - Schematic calculation

Producing Dense Strange Matter Capture K - ’s Yamazaki et al. (future) ppn ppnK ppnKK

Kaon condensation in neutron stars How the nugget is stabilized is not yet understood. However if the same mechanism is applied to (infinite) neutron star matter, kaons will condense mK*mK* ee e - → K - + n C ≥ n Nugget n

Observation For a suitable set of parameters, kaon condensation occurs at a density slightly above that of the nugget S 0 (3115). It has one proton and two neutrons per each condensed kaon just like the S 0 (pnnK - ).

Consequences Kaons condense before chiral symmetry is restored and before color superconductivity can set in. Kaons condense before chiral symmetry is restored and before color superconductivity can set in. Condensed kaons soften EOS. An intriguing possibility a la Bethe and Brown: Compact stars with mass greater than ~ 1.5 times the solar mass undergo gravitational collapse  maximum stable neutron star mass ~ 1.5  solar mass. Condensed kaons soften EOS. An intriguing possibility a la Bethe and Brown: Compact stars with mass greater than ~ 1.5 times the solar mass undergo gravitational collapse  maximum stable neutron star mass ~ 1.5  solar mass. So far no strong cases against the BB scenario exists. So far no strong cases against the BB scenario exists.

“Probing” the Early Universe By Heavy Ions

Ideal liquid above T c (?) Standard lore based on asymptotic freedom: Weakly-coupled quark-gluon plasma above T c (CERN announcement) State of matter s after the “Big Bang”: Heavy Ion

Lattice calculation & RHIC experiments indicate: Not a gas of quarks and gluons but Possibly an “ideal” liquid with viscosity/entropy  /s ~ 1/4  *, ~ 400 times smaller than (  /s) water. A strongly coupled system much like black hole horizons Just above T C, strongly bound states of light  a 1 saturate the entropy. Conjectured bound (a la Kovtun, Son and Starinets) based on holgraphic duality *

 Perfect liquid at T c +  resembling strong coupling condensed matter systems as well as black hole horizons. Discoveries  Dense strange nugget at > 3 n 0 resembling a cluster in kaon condensed neutron stars. Future