Plasmodium yoelii infection of BALB/c mice results in expansion rather than induction of CD4+ Foxp3+ regulatory T cells

Recently, we demonstrated elevated numbers of CD4(+) Foxp3(+) regulatory T (Treg) cells in Plasmodium yoelii‐infected mice contributing to the regulation of anti‐malarial immune response. However, it remains unclear whether this increase in Treg cells is due to thymus‐derived Treg cell expansion or induction of Treg cells in the periphery. Here, we show that the frequency of Foxp3(+) Treg cells expressing neuropilin‐1 (Nrp‐1) decreased at early time‐points during P. yoelii infection, whereas percentages of Helios(+) Foxp3(+) Treg cells remained unchanged. Both Foxp3(+) Nrp‐1(+) and Foxp3(+) Nrp‐1(−) Treg cells from P. yoelii‐infected mice exhibited a similar T‐cell receptor Vβ chain usage and methylation pattern in the Treg‐specific demethylation region within the foxp3 locus. Strikingly, we did not observe induction of Foxp3 expression in Foxp3(−) T cells adoptively transferred to P. yoelii‐infected mice. Hence, our results suggest that P. yoelii infection triggered expansion of naturally occurring Treg cells rather than de novo induction of Foxp3(+) Treg cells

Shot-noise-limited spin measurements in a pulsed molecular beam

Heavy diatomic molecules have been identified as good candidates for use in electron electric dipole moment (eEDM) searches. Suitable molecular species can be produced in pulsed beams, but with a total flux and/or temporal evolution that varies significantly from pulse to pulse. These variations can degrade the experimental sensitivity to changes in spin precession phase of an electri- cally polarized state, which is the observable of interest for an eEDM measurement. We present two methods for measurement of the phase that provide immunity to beam temporal variations, and make it possible to reach shot-noise-limited sensitivity. Each method employs rapid projection of the spin state onto both components of an orthonormal basis. We demonstrate both methods using the eEDM-sensitive H state of thorium monoxide (ThO), and use one of them to measure the magnetic moment of this state with increased accuracy relative to previous determinations.Comment: 12 pages, 6 figure

Light-cone distribution amplitudes of the baryon octet

We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using $N_f=2+1$ flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplitudes are observed.Comment: Update to the version published in JHE

Search for the electric dipole moment of the electron with thorium monoxide

The electric dipole moment of the electron (eEDM) is a signature of CP-violating physics beyond the Standard Model. We describe an ongoing experiment to measure or set improved limits to the eEDM, using a cold beam of thorium monoxide (ThO) molecules. The metastable $H {}^3\Delta_1$ state in ThO has important advantages for such an experiment. We argue that the statistical uncertainty of an eEDM measurement could be improved by as much as 3 orders of magnitude compared to the current experimental limit, in a first-generation apparatus using a cold ThO beam. We describe our measurements of the $H$ state lifetime and the production of ThO molecules in a beam, which provide crucial data for the eEDM sensitivity estimate. ThO also has ideal properties for the rejection of a number of known systematic errors; these properties and their implications are described.Comment: v2: Equation (11) correcte

Combining tomographic imaging and DEM simulations to investigate the structure of experimental sphere packings

We combine advanced image reconstruction techniques from computed X-ray micro tomography (XCT) with state-of-the-art discrete element method simulations (DEM) to study granular materials. This "virtual-laboratory" platform allows us to access quantities, such as frictional forces, which would be otherwise experimentally immeasurable.Comment: 20 pages, 17 figure

The ρ-meson light-cone distribution amplitudes from lattice QCD

We present the results of a lattice study of the normalization constants and second moments of the light-cone distribution amplitudes of longitudinally and transversely polarized $\rho$ mesons. The calculation is performed using two flavors of dynamical clover fermions at lattice spacings between $0.060\,\text{fm}$ and $0.081\,\text{fm}$, different lattice volumes up to $m_\pi L = 6.7$ and pion masses down to $m_\pi=150\,\text{MeV}$. Bare lattice results are renormalized non-perturbatively using a variant of the RI'-MOM scheme and converted to the $\overline{\text{MS}}$ scheme. The necessary conversion coefficients, which are not available in the literature, are calculated. The chiral extrapolation for the relevant decay constants is worked out in detail. We obtain for the ratio of the tensor and vector coupling constants $f_\rho^T/f_\rho^{\vphantom{T}} = 0.629(8)$ and the values of the second Gegenbauer moments $a_2^\parallel = 0.132(27)$ and $a_2^\perp = 0.101(22)$ at the scale $\mu = 2\,\text{GeV}$ for the longitudinally and transversely polarized $\rho$ mesons, respectively. The errors include the statistical uncertainty and estimates of the systematics arising from renormalization. Discretization errors cannot be estimated reliably and are not included. In this calculation the possibility of $\rho\to\pi\pi$ decay at the smaller pion masses is not taken into account

Deformation of Small Compressed Droplets

We investigate the elastic properties of small droplets under compression. The compression of a bubble by two parallel plates is solved exactly and it is shown that a lowest-order expansion of the solution reduces to a form similar to that obtained by Morse and Witten. Other systems are studied numerically and results for configurations involving between 2 and 20 compressing planes are presented. It is found that the response to compression depends on the number of planes. The shear modulus is also calculated for common lattices and the stability crossover between f.c.c.\ and b.c.c.\ is discussed.Comment: RevTeX with psfig-included figures and a galley macr

Fundamental Physics in Small Experiments

High energy physics aims to understand the fundamental laws of particles and their interactions at both the largest and smallest scales of the universe. This typically means probing very high energies or large distances or using high-intensity beams, which often requires large-scale experiments. A complementary approach is offered through high-precision measurements in small- and mid-scale size experiments, often at lower energies. The field of such high-precision experiments has seen tremendous progress and importance for particle physics for at least two reasons. First, they exploit synergies to adjacent areas of particle physics and benefit by many recent advances in experimental techniques. Together with intensified phenomenological explorations, these advances led to the realization that challenges associated with weak couplings or the expected suppression factors from the mass scale of new physics can be overcome with such methods. Second, many of these measurements add a new set of particle physics phenomena and observables that can be reached compared to the more conventional methodologies using high energies. Combining high-precision, smaller-scale measurements with the large-scale efforts therefore casts a wider and tighter net for possible effects originating from physics beyond the Standard Model. This report presents a broad set of small-scale research projects that could provide key new precision measurements in the areas of electric dipole moments, magnetic dipole moments, fermion flavor violation, tests of spacetime symmetries, and tests with gravity. The growing impact of these high-precision studies in high energy physics and the complementary input they provide compared to large-scale efforts warrants strong support over the next decades. In particular, EDM searches are expected to improve sensitivities by four or more orders of magnitude in the next decade or two.Comment: Snowmass 2021 Community Study on the Future of Particle Physics, Rare Processes and Precision Measurements Frontier, Topical Group RF3 Report v2: 3 additional references and one co-author adde