No Arabic abstract
We calculate for the first time the scattering cross section between lightest glueballs in $SU(2)$ pure Yang-Mills theory, which are good candidates of dark matter. In the first step, we evaluate the interglueball potential on lattice using the HAL QCD method, with several lattice spacings ($beta = 2.1, 2.2, 2.3, 2.4$, and 2.5). The systematics associated with nonzero angular momentum effect is removed by subtracting the centrifugal force. The statistical accuracy is improved by employing the cluster-decomposition error reduction technique and by using all space-time symmetries. We then determine the low energy glueball effective Lagrangian and the scattering cross section at low energy, which is compared with the observational constraint on the dark matter self-scattering. We derive the lower bound on the scale parameter of the $SU(2)$ Yang-Mills theory, as $Lambda > 60$ MeV.
We calculate the scattering cross section between two $0^{++}$ glueballs in $SU(2)$ Yang-Mills theory on lattice at $beta = 2.1, 2.2, 2.3, 2.4$, and 2.5 using the indirect (HAL QCD) method. We employ the cluster-decomposition error reduction technique and use all space-time symmetries to improve the signal. In the use of the HAL QCD method, the centrifugal force was subtracted to remove the systematic effect due to nonzero angular momenta of lattice discretization. From the extracted interglueball potential we determine the low energy glueball effective theory by matching with the one-glueball exchange process. We then calculate the scattering phase shift, and derive the relation between the interglueball cross section and the scale parameter $Lambda$ as $sigma_{phi phi} = (2 - 51) Lambda^{-2}$ (stat.+sys.). From the observational constraints of galactic collisions, we obtain the lower bound of the scale parameter, as $Lambda > 60$ MeV. We also discuss the naturalness of the Yang-Mills theory as the theory explaining dark matter.
Dark Yang-Mills sectors, which are ubiquitous in the string landscape, may be reheated above their critical temperature and subsequently go through a confining first-order phase transition that produces stochastic gravitational waves in the early universe. Taking into account constraints from lattice and from Yang-Mills (center and Weyl) symmetries, we use a phenomenological model to construct an effective potential of the semi quark-gluon plasma phase, from which we compute the gravitational wave signal produced during confinement for numerous gauge groups. The signal is maximized when the dark sector dominates the energy density of the universe at the time of the phase transition. In that case, we find that it is within reach of the next-to-next generation of experiments (BBO, DECIGO) for a range of dark confinement scales near the weak scale.
The correlation between the invisible Higgs branching ratio ($B_h^{rm inv} $) vs. dark matter (DM) direct detection ($sigma_p^{rm SI}$) in Higgs portal DM models is usually presented in the effective field theory (EFT) framework. This is fine for singlet scalar DM, but not in the singlet fermion DM (SFDM) or vector DM (VDM) models. In this paper, we derive the explicit expressions for this correlation within UV completions of SFDM and VDM models with Higgs portals, and discuss the limitation of the EFT approach. We show that there are at least two additional hidden parameter in $sigma_p^{rm SI}$ in the UV completions: the singlet-like scalar mass $m_2$ and its mixing angle $alpha$ with the SM Higgs boson ($h$). In particular, if the singlet-like scalar is lighter than the SM Higgs boson ($m_2 < m_h cos alpha / sqrt{1 + cos^2 alpha}$), the collider bound becomes weaker than the one based on EFT.
In this paper, we probe the effect of noncommutativity on the entanglement of purification in the holographic set up. We followed a systematic analytical approach in order to compute the holographic entanglement entropy corresponding to a strip like subsystem. The entropic c-function has been computed and the effect of noncommutativity has been noted. We then move on to compute the minimal cross-section area of the entanglement wedge by considering two disjoint subsystems. On the basis of $E_P = E_W$ duality, this leads to the holographic computation of the entanglement of purification. The correlation between two subsystems, namely, the holographic mutual information has also been computed. Finally we consider a black hole geometry with a noncommutative parameter and study the influence of both noncommutativity and finite temperature on the entanglement of purification and mutual information.
Inspired in the Standard Model of Elementary Particles, the Einstein Yang-Mills Higgs action with the Higgs field in the SU(2) representation was proposed in Class. Quantum Grav. 32 (2015) 045002 as the element responsible for the dark energy phenomenon. We revisit this action emphasizing in a very important aspect not sufficiently explored in the original work and that substantially changes its conclusions. This aspect is the role that the Yang-Mills Higgs interaction plays at fixing the gauge for the Higgs field, in order to sustain a homogeneous and isotropic background, and at driving the late accelerated expansion of the Universe by moving the Higgs field away of the minimum of its potential and holding it towards an asymptotic finite value. We analyse the dynamical behaviour of this system and supplement this analysis with a numerical solution whose initial conditions are in agreement with the current observed values for the density parameters. This scenario represents a step towards a successful merging of cosmology and well-tested particle physics phenomenology.