New States of Strongly Interacting Astrophysical Matter

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

2. 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%

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

4. 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?

5. QCD Answer • QCD on lattice explains the proton mass • within ~ 10% . “ 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 (cSB)”

6. Order Parameter _ Quark condensate: <qq> ≠ 0 cS broken = 0 cS restored _ • <qq> ≈ -(0.23±0.03 GeV)3→ Proton • mass ≈ 1 GeV • What happens when <qq>→ 0 ? _

7. 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

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

10. Effective Field Theories QCD cannot address directly the problem of going toward the critical point Tc/nc, so we need to resort to effective field theories • Tools at our disposal: • NLs: Nonlinear sigma model with pseudo- • Goldstone bosons (p, K, …) • HLS: Hidden local symmetry model • with p, K, light vectors (r,w,K*, …) • etc …

11. 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)”

12. Predictions with HLS As <qq>→ 0, i.e., n (or T)→ nc (or Tc) ¯ • Theory well defined at this limit! • Hidden gauge coupling g <qq> → 0 • Pion decay constant fp ~ F(<qq>) → 0 • Even away from the limit, hadron mass • (except for p’s) satisfies “BR scaling”; • e.g., in density • m(n)/m(0) ≈ fp (n)/fp (0)for n ≤ n0 • ≈ g(n)/g(0) for n > n0 • wheren0 = 0.16 fm-3 nuclear matter ¯ ¯

13. Nature There are indications that the scaling is operative up to n0 mw (n0)/mw≈ fp(n0)/fp ≈ 0.8 Bonn: CBELSA/TAPS Collaboration g+A→w+X→p0g+X’ KEK: Deeply bound pionic nuclei

14. High precision measurements at GSI from 2007

15. A dense new state above n0 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

16. Mechanism Turns out to be surprisingly simple Huge attraction from two main sources: • Attractive K- - nuclear interaction K  - (1/fp*)2  density ≡ - A w A • Density counters EcSB, tending to restore cS  - c SKN  density ≡ - B A+B ~ 200 MeV at n  n0 =0.16 fm-3

17. Kaon Potential

18. Discovery of strangeness nugget KEK 2004 A bound pnnK – = “ S0 (3115)” BE=mp + 2mn + mK– mS =194 ±5 MeV Average density ~ 3 n0 Strong binding overcomes compression energy!

19. Embed K- Schematic calculation

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

21. 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* me e- → K- + n nC ≥ nNugget n

22. Observation For a suitable set of parameters, kaon condensation occurs at a density slightly above that of the nugget S0 (3115) . It has one proton and two neutrons per each condensed kaon just like the S0 (pnnK-) .

23. Consequences • 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. • So far no strong cases against the BB scenario exists.

25. “Probing” the Early Universe By Heavy Ions

26. Ideal liquid above Tc (?) State of matter 10-6s after the “Big Bang”: Heavy Ion Standard lore based on asymptotic freedom: Weakly-coupled quark-gluon plasma above Tc (CERN announcement)

27. Lattice calculation & RHIC experiments indicate: Not a gas of quarks and gluons but • A strongly coupled system • much like black hole horizons • Possibly an “ideal” liquid • with viscosity/entropy • h/s ~ 1/4p*, ~ 400 times • smaller than (h/s)water. • Just above TC , strongly bound • states of light p, s, r, a1 • saturate the entropy. * Conjectured bound (a la Kovtun, Son and Starinets) based on holgraphic duality

28. Discoveries • Perfect liquid at Tc + e, resembling strong coupling condensed matter systems as well as black hole horizons. • Dense strange nugget at > 3 n0 resembling a cluster in kaon condensed neutron stars. Future