The proton is one of the main building blocks of all visible matter in the Universe
. Among its intrinsic properties are its electric charge, mass and spin
. These properties emerge from the complex ...dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics
. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering
. An example is the highly precise measurement of the electric charge radius of the proton
. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton
from our measurement. We used a variety of models
and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics
. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.
To estimate the efficacy of daily administration of 5 mg compared with 10 mg of mifepristone for the treatment of uterine myomas.
One hundred women were randomly assigned to receive oral mifepristone ...5 mg or 10 mg daily for 3 months (50 per group). Abdominal ultrasonography was performed before treatment, at 45 days, and at 3 months to evaluate leiomyoma and uterine volumes. Endometrial biopsy specimens were taken before and after treatment. Efficacy was estimated by the reduction percentages of the leiomyoma and uterine volumes.
After 90 days treatment there was a 45% (95% confidence interval CI 37-54, P<.001) and a 57% (95% CI 48-67, P<.001) reduction in the leiomyoma volume in the 10-mg and 5-mg groups, respectively, and one of 40% (95% CI 34-46, P=.002), and 36% (95% CI 31-40, P<.001), respectively, in the uterine volume. Symptomatic improvement was noted, and the prevalence of symptoms diminished significantly. There were no significant differences in reduction of volume and symptoms in the treatment groups, P>.05 in all cases. After treatment, 44 of 49 (89.8%) women from the mifepristone 10 mg group and 45 of 50 (90.0%) from the 5-mg group, respectively, were amenorrheic (P=.487). Endometrial biopsy after treatment showed simple hyperplasia in 1 of 50 (2.0%) in the mifepristone 10 mg group.
Five-milligram doses of mifepristone produce reductions in leiomyoma and uterine volumes and symptomatic improvement similar to 10-mg doses.
I.
The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics ...and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities
that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities
map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades
. Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.
We measure ^{2}H(e,e^{'}p)n cross sections at 4-momentum transfers of Q^{2}=4.5±0.5 (GeV/c)^{2} over a range of neutron recoil momenta p_{r}, reaching up to ∼1.0 GeV/c. We obtain data at fixed ...neutron recoil angles θ_{nq}=35°, 45°, and 75° with respect to the 3-momentum transfer qover →. The new data agree well with previous data, which reached p_{r}∼500 MeV/c. At θ_{nq}=35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta p_{r}>700 MeV/c.
We report new pion electroproduction measurements in the
Δ
(
1232
)
resonance, utilizing the SHMS - HMS magnetic spectrometers of Hall C at Jefferson Lab. The data focus on a region that exhibits a ...strong and rapidly changing interplay of the mesonic cloud and quark-gluon dynamics in the nucleon. The results are in reasonable agreement with models that employ pion cloud effects and chiral effective field theory calculations, but at the same time they suggest that an improvement is required to the theoretical calculations and provide valuable input that will allow their refinements. The data illustrate the potential of the magnetic spectrometers setup in Hall C towards the study the
Δ
(
1232
)
resonance. These first reported results will be followed by a series of measurements in Hall C, that will expand the studies of the
Δ
(
1232
)
resonance offering a high precision insight within a wide kinematic range from low to high momentum transfers.
The feasibility of expression library immunization against the pathogenic bacterium
Neisseria meningitidis was studied. A genomic library of
N. meningitidis serogroup B strain CU385, containing 6000 ...individual clones, was constructed and divided into 10 sublibraries. Immunization of BALB/c mice with plasmid DNA from six sublibraries induced a humoral response, with recognition of several meningococcal proteins by Western blot. Three of these sublibraries elicited bactericidal antibodies against the homologous strain, and sera from mice immunized with one of these sublibraries reduced significantly the number of viable bacteria in blood of infant rats challenged with
N. meningitidis. In addition, after DNA immunization, mice were boosted intraperitoneally with 5 × 10
2 colony forming units of strain CU385. Mice immunized with nine of the 10 libraries developed bactericidal antibodies 1 week after the boost and controls did not, demonstrating the priming capacity and specificity of our immunization strategy. Our study demonstrates, for the first time, that genomic immunization offers a novel approach for screening possible vaccine candidates against
N. meningitidis.
The GlueX Start Counter Detector Pooser, E.; Barbosa, F.; Boeglin, W. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2019, Letnik:
927, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The design, simulation, fabrication, calibration, and performance of the GlueX Start Counter detector are described. The Start Counter was designed to operate at integrated rates of up to 9 MHz with ...a timing resolution in the range of 500 to 825 ps (FWHM). The Start Counter provides excellent solid angle coverage, a high degree of segmentation for background rejection, and can be utilized in the level 1 trigger for the experiment. It consists of a cylindrical array of 30 thin scintillators with pointed ends that bend towards the beam line at the downstream end. Magnetic field insensitive silicon photomultiplier detectors were used as the light sensors.
We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q^{2}) up to 15.75 (GeV/c)^{2}. Combined with existing data, these provide an ...improved extraction of the proton magnetic form factor at high Q^{2} and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q^{2} and attributed to hard two-photon exchange (TPE) effects, extending to 8 (GeV/c)^{2} the range of Q^{2} for which a discrepancy is established at >95% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q^{2}.
The present and future of QCD Al-bataineh, A.; Avakian, H.; Barnea, N. ...
Nuclear physics. A,
07/2024, Letnik:
1047, Številka:
C
Journal Article
Recenzirano
Odprti dostop
This White Paper presents an overview of the current status and future perspective of QCD research, based on the community inputs and scientific conclusions from the 2022 Hot and Cold QCD Town ...Meeting. We present the progress made in the last decade toward a deep understanding of both the fundamental structure of the sub-atomic matter of nucleon and nucleus in cold QCD, and the hot QCD matter in heavy ion collisions. We identify key questions of QCD research and plausible paths to obtaining answers to those questions in the near future, hence defining priorities of our research over the coming decades.
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