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The Fast Life of Holographic Mesons: Spectral Functions and Decay Widths

Explore the behavior of strongly coupled QCD using string theory tools and gauge/gravity duality. Investigate the masses, lifetimes, and spectral functions of holographic mesons. Examine the effects of changing momentum and other parameters.

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The Fast Life of Holographic Mesons: Spectral Functions and Decay Widths

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  1. Quark Matter 2008, Jaipur, India The fast life of holographic mesons Aninda Sinha Perimeter Institute, Canada. with Robert Myers arXiv:0802.nnnn

  2. PLAN I) Motivation and setup II) Spectral functions of holographic mesons, decay widths III) Conclusion

  3. I) Motivation and setup Behaviour of strongly coupled QCD is of interest to RHIC and early universe cosmology. Unfortunately, theoretical tools are rather limited. Recently, string theory tools involving gauge/gravity duality have been used to gain some insight into the nature of this interesting regime. limitation: large NC and large ’t Hooft coupling

  4. AdS/CFT relates N=4, d=4 supersymmetric Yang Mills theory and its deformations to a theory of gravity in Anti-de-Sitter space (a space with negative cosmological constant) arising as a solution to d=10 superstring theory. In particular, the effective gravity theory is on AdS5 x S5. The strongly coupled regime of the gauge theory is mapped into a weakly coupled gravity theory. Idea is to try and do calculations using the gravity theory to gain some insight into the strong coupling region of the gauge theory.

  5. QCD N=4 SYM confinement, discrete spectrum, scattering, . . . . conformal, continuous spectrum, no S-matrix, SUSY, . . . . T=0 very different !! strongly-coupled plasma of gluons & fundamental matter deconfined, screening, finite corr. lengths, . . . strongly-coupled plasma of gluons & adjoint matter deconfined, screening, finite corr. lengths, . . . T>TC quite similar !! cf runs to weak coupling remains strongly-coupled T>>TC very different !!

  6. RECIPE FOR HOLOGRAPHIC QUARK GLUON SOUP [Aharony, Fayazuddin, Maldacena; Karch, Katz; Kruczenski, Mateos, Myers, Winters] 1) Start with black hole in AdS to get finite temperature, have deconfined adjoint matter II) Add D-brane to get flavour Free quark III) String falls into black hole and melts mesons Baryon density n causes brane to reach horizon q IV) Mass of meson, decay controlled by baryon density and geometry of D-brane (quark bare mass and condensate depend on these)

  7. SPECIFIC QUESTION: What can we say about the masses and lifetimes of holographic mesons at strong coupling? What is the nature of the spectral functions with changing momentum and other parameters? BROADER QUESTION (for the future): Do these features have anything in common with Lattice data and/or real world?

  8. Spectral functions from AdS/CFT F,G,R are functionsofr which is the holographic direction. Spectral function is defined as For us is large. Can recast in terms of an effective Schrodinger equation

  9. Behaviour of effective holographic potential with changing momentum Bound state Holographic direction Horizon

  10. Behaviour of effective holographic potential with changing momentum

  11. Behaviour of effective holographic potential with changing momentum

  12. Behaviour of effective holographic potential with changing momentum

  13. Behaviour of effective holographic potential with changing momentum

  14. Behaviour of effective holographic potential with changing momentum

  15. Behaviour of effective holographic potential with changing momentum

  16. Behaviour of effective holographic potential with changing momentum

  17. II) Spectral functions and widths = 0 0.06 0.15 0.25 q n Quasiparticles

  18. nq = 0.25

  19. Speed limit from spectral peaks[Liu, Rajagopal, Wiedemann; Mateos, Myers, Thomson; Ejaz, Faulkner, Liu, Rajagopal, Wiedemann; Athanasiou, Liiu, Rajagopal; Myers, AS] nq = 0.25 Real part of quasinormal frequency

  20. Dispersion relations for first 3 peaks for different parameters vmax = 0.9954 vmax = 0.6512 vmax = 0.3427 At same temperature, higher vmax means higher bare quark mass. Equivalently, keeping bare quark mass fixed, higher vmax means lower temperature.

  21. Widths as function of momenta[Myers, AS] V=0.34 V=0.65 V=0.99 Location where effective potential has no minima

  22. Conclusion Holographic methods suggest finite velocity effects in the dispersion relations. Arise quite generally due to red-shift in the dual gravity picture. Finite baryon density induces quasiparticle widths to grow dramatically with momenta. Can be quite general but needs further investigation. THANKS FOR LISTENING

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