Related papers: Chiral order and fluctuations in multi-flavour QCD
Massive fermions produced through weak charged interactions possess a definite chirality, which is not conserved during free propagation, leading to chiral oscillations. Neutrinos also exhibit flavor oscillations. These phenomena have been…
We present positivity bounds, derived from the principles of analyticity, unitarity and crossing symmetry, that constrain the low-energy constants of chiral perturbation theory. Bounds are produced for 2, 3 or more flavours in meson-meson…
Within Chiral Perturbation Theory (CHPT) we compute the form factors A, V and $\gamma = A/V$ in the $\pi \to \nu l \gamma$ decay to $O(p^6)$. A and $\gamma$ obtain corrections of order 25%.
We study three-flavor QCD in a uniform magnetic field using chiral perturbation theory ($\chi$PT). We construct the vacuum free energy density, quark condensate shifts induced by the magnetic field and the renormalized magnetization to…
Wilson chiral perturbation theory (WChPT) is the effective field theory describing the long- distance properties of lattice QCD with Wilson or twisted-mass fermions. We consider here WChPT for the theory with two light flavors of Wilson…
Scaling behavior is analyzed for the two-flavor QCD lattice gauge theory chiral transition. Leading scaling behavior and correction to leading scaling from lattice spacing effects are examined for the quark condensate. Scaling predictions…
During the expansion of a heavy ion collision, the system passes close to the $O(4)$ critical point of QCD, and thus the fluctuations of the order parameter $(\sigma, \vec{\pi})$ are expected to be enhanced. Our goal is to compute how these…
The interplay between quantum and thermal fluctuations in the presence of quenched random disorder is a long-standing open theoretical problem which has been made more urgent by advances in modern experimental techniques. The fragility of…
The chiral symmetry of QCD with two massless quark flavours gets restored in a non-analytic chiral phase transition at finite temperature and zero density. Whether this is a first-order or a second-order transition has not yet been…
In QCD simulations at small lattice spacings, the topological charge Q evolves very slowly and, if this quantity is not properly equilibrated, we could get incorrect results for physical quantities, or incorrect estimates of their errors.…
Chiral perturbation theory in the two--flavour sector allows one to analyse Green functions in QCD in the limit where the strange quark mass is considered to be large in comparison to the external momenta and to the light quark masses m_u…
We present the results from our two-loop calculations of masses, decay-constants, vacuum-expectation-values and the $K_{\ell4}$ form-factors in three-flavour Chiral Perturbation Theory (CHPT). We use this to fit the $L_i^r$ to two-loops and…
We investigate a chirally imbalanced medium in the context of the two-flavor Nambu--Jona-Lasinio model using both the large-$N_c$ (LN) and beyond large-$N_c$ (BLN) approximations. To incorporate BLN effects, we consider the optimized…
Baryon number fluctuations are believed to be good signatures of the QCD phase transition and its CP. Since the fluctuations are proportional to the various order baryon-number susceptibilities and the quark-number density is related to the…
Correct phenomenological description of ferroelectric phase transitions in barium titanate requires accounting for eighth-order terms in the free energy expansion, in addition to the conventional sixth-order contributions. Another unusual…
We study a quasi-2D classical Landau-Ginzburg-Wilson effective field theory in the presence of quenched disorder in which incommensurate charge-density wave and superconducting orders are intertwined. The disorder precludes long-range…
We use a cluster algorithm to study the critical behavior of strongly coupled lattice QCD in the chiral limit. We show that the finite temperature chiral phase transition belongs to the O(2) universality class as expected. When we compute…
We construct the chiral perturbation theory for two-color QCD with two quark flavors as an effective theory on the SO(6)/SO(5) coset space. This formulation turns out to be particularly useful for extracting the physical content of the…
We apply optimized perturbation theory to the quark-meson model at finite temperature T and quark chemical potential mu. The effective potential is calculated to one loop both in the chiral limit and at the physical point and used to study…
I describe recent developments in quenched chiral perturbation theory (QChPT) and the status of weak matrix elements involving light quarks. I illustrate how, with improved statistical errors, and with calculations of the masses of baryons…