Thesis

Confinement and exotic hadrons with Lattice QCD

• Call:

  IDPASC Portugal - PHD Programme 2014

• Academic Year:

  2014 /2015

• Domain:

  Theoretical Particle Physics

• Supervisor:

  Marco Cardoso

• Co-Supervisor:

  Pedro Bicudo

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Centro de Física Teórica de Partículas

• Abstract:

  Confinement and exotic hadrons with Lattice QCD Quantum Chromodynamics (QCD) is the theory of quarks and gluons, particles constituting most of the visible matter. QCD is non-perturbative and the only known approach to eventually solve QCD is computing the Path Integral with Monte-Carlo techniques, eg Lattice QCD [1-5. We simulate tiny parts of the Universe at the fm scale of lattices with up to 100^4 space-time points. The QCD theory of particles and fields, with non-commutative groups such as the SU(3) 'colour' group and the SU(6) 'flavour' group, is very beautiful, and discretizing in on a lattice makes it even more interesting [1-5]. However this is computationally very demanding, and Lattice QCD is a Computational Physics topic [6-8]. We utilize the most efficient computers we can find. In CFTP, IST, U. Lisboa, we have been developing codes in C++ and CUDA to run the Graphics Processing Units (GUPs); and we have several servers with state of the art GPUs, parly supported by NVIDIA grants [9-11]. Our Lattice QCD students become outstanding programmers, able to address the most difficult numerical problems a physicist may solve. Our Lattice QCD group at CFTP collaborates with the Lattice QCD group of the University of Coimbra (O. Oliveira and P. J. Silva), in common research and sharing computational facilities. We also manage joint FCT and European Union (Horizon 2020) projects. Our collaboration is PtQCD, http://nemea.ist.utl.pt/~ptqcd/ Many open problems remain to be solved in Lattice QCD, needing both new technical improvements and new theoretical concepts. At CFTP we are able presently to study many topics such as confinement and chiral symmetry at the large finite temperatures [12-15] of the early universe and of heavy ion collisions or bound states and resonances such with few quarks and gluons [16-19], the hadrons (mesons, baryons, hybrids, glueballs, tetraquarks, pentaquarks). The study of these problems in Lattice QCD, developing new Lattice QCD techniques [20-22] or new effective models [23-25] for quarks and gluons inspired in Lattice QCD, constitute the plan of the Thesis. References: [1] Confinement of Quarks K. G. Wilson Phys.Rev. D10 (1974) 2445-2459 [2] The Renormalization group and the epsilon expansion K.G. Wilson, J. B. Kogut Phys.Rept. 12 (1974) 75-200 [3] Hamiltonian Formulation of Wilson's Lattice Gauge Theories J. B. Kogut, Leonard Susskind Phys.Rev. D11 (1975) 395-408 [4] Compact Gauge Fields and the Infrared Catastrophe A. M. Polyakov Phys.Lett. B59 (1975) 82-84 [5] Quark Confinement and Topology of Gauge Groups A. M. Polyakov Nucl.Phys. B120 (1977) 429-458 [6] Monte Carlo Study of Quantized SU(2) Gauge Theory M. Creutz Phys.Rev. D21 (1980) 2308-2315 [7] A Monte Carlo Study of SU(2) Yang-Mills Theory at Finite Temperature L. D. McLerran, B. Svetitsky Phys.Lett. B98 (1981) 195 [8] Quark Liberation at High Temperature: A Monte Carlo Study of SU(2) Gauge Theory L. D. McLerran, B. Svetitsky Phys.Rev. D24 (1981) 450 [9] SU(2) Lattice Gauge Theory Simulations on Fermi GPUs N. Cardoso, P. Bicudo J.Comput.Phys. 230 (2011) 3998-4010 [10] Generating SU(Nc) pure gauge lattice QCD configurations on GPUs with CUDA and OpenMP N. Cardoso, P. Bicudo Comput.Phys.Commun. 184 (2013) 509-518 [11] Landau Gauge Fixing on GPUs N. Cardoso, P. J. Silva , P. Bicudo, O. Oliveira, Comput.Phys.Commun. 184 (2013) 124-129 [12] Lattice QCD computation of the SU(3) String Tension critical curve N. Cardoso, P. Bicudo Phys.Rev. D85 (2012) 077501 [13] Running Gluon Mass from Landau Gauge Lattice QCD Propagator O. Oliveira, P. Bicudo J.Phys. G38 (2011) 045003 [14] Gluon screening mass at finite temperature from Landau gauge gluon propagator in lattice QCD P.J. Silva, O. Oliveira , P. Bicudo, N. Cardoso, Phys.Rev. D89 (2014) 074503 [15] Inside the SU(3) quark-antiquark QCD flux tube: screening versus quantum widening N. Cardoso, M. Cardoso, P. Bicudo Phys.Rev. D88 (2013) 054504 [16] Study of the gluon-quark-antiquark static potential in SU(3) lattice QCD P. Bicudo, M. Cardoso, O. Oliveira Phys.Rev. D77 (2008) 091504 [17] First study of the three-gluon static potential in Lattice QCD M. Cardoso, P. Bicudo Phys.Rev. D78 (2008) 074508 [18] Colour Fields Computed in SU(3) Lattice QCD for the Static Tetraquark System N. Cardoso, M. Cardoso, P. Bicudo Phys.Rev. D84 (2011) 054508 [19]Variational study of the flux tube recombination in the two quarks and two quarks system in Lattice QCD M. Cardoso, N. Cardoso, P. Bicudo Phys.Rev. D86 (2012) 014503 [20] Effective Polyakov line action from strong lattice couplings to the deconfinement transition J. Greensite, K. Langfeld Published in Phys.Rev. D88 (2013) 074503 [21] Gauge cooling in complex Langevin for QCD with heavy quarks E. Seiler, D. Sexty, I.-O. Stamatescu Phys.Lett. B723 (2013) 213-216 [22] Simulating full QCD at nonzero density using the complex Langevin equation D. Sexty Published in Phys.Lett. B729 (2014) 108-111 [23] Decays of tetraquark resonances in a two-variable approximation to the triple flip-flop potential P. Bicudo, M. Cardoso Phys.Rev. D83 (2011) 094010 [24] Lattice QCD signal for a bottom-bottom tetraquark P. Bicudo, M. Wagner Phys.Rev. D87 (2013) 11, 114511 [25] Matrix model for deconfinement in a SU(Nc) gauge theory in 2+1 dimensions P. Bicudo, R. D. Pisarski, E. Seel Phys.Rev. D89 (2014) 085020