Baryons, multi-hadron systems, and composite dark matter in non-relativistic QCD

We provide a formulation of potential non-relativistic quantum chromodynamics (pNRQCD) suitable for calculating binding energies and matrix elements of generic hadron and multi-hadron states made of heavy quarks in $SU(N_c)$ gauge theory using quantum Monte Carlo techniques. We compute masses of quarkonium and triply-heavy baryons in order to study the perturbative convergence of pNRQCD and validate our numerical methods. Further, we study $SU(N_c)$ models of composite dark matter and provide simple power series fits to our pNRQCD results that can be used to relate dark meson and baryon masses to the fundamental parameters of these models. For many systems comprised entirely of heavy quarks, the quantum Monte Carlo methods employed here are less computationally demanding than lattice field theory methods, although they introduce additional perturbative approximations. The formalism presented here may therefore be particularly useful for predicting composite dark matter properties for a wide range of $N_c$ and heavy fermion masses.Comment: 39 pages, 24 figure

Proton decay from quark and lepton compositeness

Within a chiral $SU(15)$ gauge theory in which the Standard Model fermions are bound states of massless preons, we show that proton-decay operators are likely induced at the compositeness scale, $\Lambda_{\rm pre}$. Our estimate of the limit imposed by searches for proton decays is $\Lambda_{\rm pre} > 10^4 \, {\rm TeV}^{1/2} \, C_8^{1/4} \, m_{\cal Q}^{1/2}$, where $C_8$ is a rescaled coefficient of an 8-prebaryon operator induced by $SU(15)$ dynamics, and $m_{\cal Q}$ is the mass of a composite vectorlike quark. The latter has a lower limit related to the mass of a composite vectorlike lepton, which in turn is required by LHC searches to be above 1 TeV. For $C_8$ in the $10^{-5} - 1$ range, the lower limit on $\Lambda_{\rm pre}$ varies between $3 \times 10^3$ TeV and $5 \times 10^4$ TeV. We point out that exotic proton decay modes, into a $\pi^+$ and a heavy right-handed neutrino, could be observed using the Super-Kamiokande or DUNE detectors.Comment: 24 pages, 5 figure

Tetraquarks made of sufficiently heavy quarks are bound in QCD

Tetraquarks, bound states composed of two quarks and two antiquarks, have been the subject of intense study but have yet to be understood from first principles. Previous studies of fully-heavy tetraquarks in nonrelativistic effective field theories of quantum chromodynamics (QCD) suggest different conclusions for their existence. We apply variational and Green's function Monte Carlo methods to compute tetraquarks' ground- and excited-state energies in potential nonrelativistic QCD. We robustly demonstrate that fully-heavy tetraquarks are bound in QCD for sufficiently heavy quark masses. We also predict the masses of tetraquark bound states comprised of $b$ and $c$ quarks, which are experimentally accessible, and suggest possible resolutions for previous theoretical discrepancies.Comment: 10 pages, 5 figur

Proton decay from quark and lepton compositeness

Abstract Within a chiral SU(15) gauge theory in which the Standard Model fermions are bound states of massless preons, we show that proton-decay operators are likely induced at the compositeness scale, Λpre. Our estimate of the limit imposed by searches for proton decays is Λpre > 104 TeV1/2 C 8 1 / 4 m Q 1 / 2 $${C}_8^{1/4}\ {m}_{\mathcal{Q}}^{1/2}$$ , where C 8 is a rescaled coefficient of an 8-prebaryon operator induced by SU(15) dynamics, and m Q $${m}_{\mathcal{Q}}$$ is the mass of a composite vectorlike quark. The latter has a lower limit related to the mass of a composite vectorlike lepton, which in turn is required by LHC searches to be above 1 TeV. For C 8 in the 10 −5 – 1 range, the lower limit on Λpre varies between 3 × 103 TeV and 5 × 104 TeV. We point out that exotic proton decay modes, into a π + and a heavy right-handed neutrino, could be observed using the Super-Kamiokande or DUNE detectors

Matching the Standard Model to HQET and NRQCD

We find the leading electro-weak corrections to the HQET/NRQCD Lagrangian. These corrections appear in the Wilson coefficients of the two and four quark operators and are considered here up to $\mathcal{O}(1/m^3)$ at one-loop order. The two quark operators up to this order will include new CP-violating terms, which we derived analogously to the CP preserving QCD result at one-loop order.Comment: 17 pages, 4 figure

Fermion geometry and the renormalization of the Standard Model Effective Field Theory

Abstract : The geometry of field space governs on-shell scattering amplitudes. We formulate a geometric description of effective field theories which extends previous results for scalars and gauge fields to fermions. The field-space geometry reorganizes and simplifies the computation of quantum loop corrections. Using this geometric framework, we calculate the fermion loop contributions to the renormalization group equations for bosonic operators in the Standard Model Effective Field Theory up to mass dimension eight

Fermion geometry and the renormalization of the Standard Model Effective Field Theory

Abstract The geometry of field space governs on-shell scattering amplitudes. We formulate a geometric description of effective field theories which extends previous results for scalars and gauge fields to fermions. The field-space geometry reorganizes and simplifies the computation of quantum loop corrections. Using this geometric framework, we calculate the fermion loop contributions to the renormalization group equations for bosonic operators in the Standard Model Effective Field Theory up to mass dimension eight

Fermion Geometry and the Renormalization of the Standard Model Effective Field Theory

The geometry of field space governs on-shell scattering amplitudes. We formulate a geometric description of effective field theories which extends previous results for scalars and gauge fields to fermions. The field-space geometry reorganizes and simplifies the computation of quantum loop corrections. Using this geometric framework, we calculate the fermion loop contributions to the renormalization group equations for bosonic operators in the Standard Model Effective Field Theory up to mass dimension eight.Comment: 28 page

Long-term neurological symptoms after acute COVID-19 illness requiring hospitalization in adult patients: insights from the ISARIC-COVID-19 follow-up study

in this study we aimed to characterize the type and prevalence of neurological symptoms related to neurological long-COVID-19 from a large international multicenter cohort of adults after discharge from hospital for acute COVID-19

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence