113 research outputs found
Supermultiplets of the N=1 supersymmetric Yang-Mills theory in the continuum limit
The spectrum of N=1 supersymmetric Yang-Mills theory, calculated on the
lattice, is presented. The masses have been determined on three different
lattice spacings and extrapolated towards vanishing gluino mass. We present the
extrapolation to the continuum limit which is consistent with the formation of
degenerate supermultiplets.Comment: 7 pages, 4 figures; Proceedings of the 33rd International Symposium
on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe International
Conference Center, Kobe, Japa
The low-lying spectrum of N=1 supersymmetric Yang-Mills theory
The spectrum of the lightest bound states in N=1 supersymmetric Yang-Mills
theory with SU(2) gauge group, calculated on the lattice, is presented. The
masses have first been extrapolated towards vanishing gluino mass and then to
the continuum limit. The final picture is consistent with the formation of
degenerate supermultiplets.Comment: 6 pages; 3 figures; proceedings of the EPS-HEP Conference 2015, 22-29
July 2015, Vienna, Austri
The light bound states of supersymmetric SU(2) Yang-Mills theory
Supersymmetry provides a well-established theoretical framework for
extensions of the standard model of particle physics and the general
understanding of quantum field theories. We summarise here our investigations
of N=1 supersymmetric Yang-Mills theory with SU(2) gauge symmetry using the
non-perturbative first-principles method of numerical lattice simulations. The
strong interactions of gluons and their superpartners, the gluinos, lead to
confinement, and a spectrum of bound states including glueballs, mesons, and
gluino-glueballs emerges at low energies. For unbroken supersymmetry these
particles have to be arranged in supermultiplets of equal masses. In lattice
simulations supersymmetry can only be recovered in the continuum limit since it
is explicitly broken by the discretisation. We present the first continuum
extrapolation of the mass spectrum of supersymmetric Yang-Mills theory. The
results are consistent with the formation of supermultiplets and the absence of
non-perturbative sources of supersymmetry breaking. Our investigations also
indicate that numerical lattice simulations can be applied to non-trivial
supersymmetric theories.Comment: 19 pages, 6 figure
Influence of topology on the scale setting
Recently a new method to set the scale in lattice gauge theories, based on
the gradient flow generated by the Wilson action, has been proposed, and the
systematic errors of the new scales t0 and w0 have been investigated by various
groups. The Wilson flow provides also an interesting alternative smoothing
procedure in particular useful for the measurement of the topological charge as
a pure gluonic observable. We show the viability of this method for N=1
supersymmetric Yang-Mills theory by analysing the configurations produced by
the DESY-Muenster collaboration. For increasing flow time the topological
charge quickly approaches near-integer values. The topological susceptibility
has been measured for different fermion masses and its value is observed to
approach zero in the chiral limit. Finally, the relation between the scale
defined by the Wilson flow and the topological charge has been investigated,
demonstrating a correlation between these two quantities.Comment: 17 pages, 12 figure
Magnetic susceptibility of QCD matter and its decomposition from the lattice
Bali GS, Endrödi G, Piemonte S. Magnetic susceptibility of QCD matter and its decomposition from the lattice. Journal of High Energy Physics . 2020;2020(7): 183.We determine the magnetic susceptibility of thermal QCD matter by means of first principles lattice simulations using staggered quarks with physical masses. A novel method is employed that only requires simulations at zero background field, thereby circumventing problems related to magnetic flux quantization. After a careful continuum limit extrapolation, diamagnetic behavior (negative susceptibility) is found at low temperatures and strong paramagnetism (positive susceptibility) at high temperatures. We revisit the decomposition of the magnetic susceptibility into spin- and orbital angular momentum- related contributions. The spin term - related to the normalization of the photon lightcone distribution amplitude at zero temperature - is calculated non-perturbatively and extrapolated to the continuum limit. Having access to both the full magnetic susceptibility and the spin term, we calculate the orbital angular momentum contribution for the first time. The results reveal the opposite of what might be expected based on a free fermion picture. We provide a simple parametrization of the temperature- and magnetic field-dependence of the QCD equation of state that can be used in phenomenological studies
Ward identities in supersymmetric SU(3) Yang-Mills theory on the lattice
The introduction of a space-time lattice as a regulator of field theories
breaks symmetries associated with continuous space-time, i.e.\ Poincar{\'e}
invariance and supersymmetry. A non-zero gluino mass in the supersymmetric
Yang-Mills theory causes an additional soft breaking of supersymmetry. We
employ the lattice form of SUSY Ward identities, imposing that their continuum
form would be recovered when removing the lattice regulator, to obtain the
critical hopping parameter where broken symmetries can be recovered.Comment: Presented at Lattice 2017, the 35th International Symposium on
Lattice Field Theory at Granada, Spain (18-24 June 2017
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