Showing papers on "Proton published in 2020"

Precise test of quantum electrodynamics and determination of fundamental constants with HD+ ions.

Abstract: Bound three-body quantum systems are important for fundamental physics1,2 because they enable tests of quantum electrodynamics theory and provide access to the fundamental constants of atomic physics and to nuclear properties. Molecular hydrogen ions, the simplest molecules, are representative of this class3. The metastability of the vibration–rotation levels in their ground electronic states offers the potential for extremely high spectroscopic resolution. Consequently, these systems provide independent access to the Rydberg constant (R∞), the ratios of the electron mass to the proton mass (me/mp) and of the electron mass to the deuteron mass (me/md), the proton and deuteron nuclear radii, and high-level tests of quantum electrodynamics4. Conventional spectroscopy techniques for molecular ions5–14 have long been unable to provide precision competitive with that of ab initio theory, which has greatly improved in recent years15. Here we improve our rotational spectroscopy technique for a sympathetically cooled cluster of molecular ions stored in a linear radiofrequency trap16 by nearly two orders in accuracy. We measured a set of hyperfine components of the fundamental rotational transition. An evaluation resulted in the most accurate test of a quantum-three-body prediction so far, at the level of 5 × 10−11, limited by the current uncertainties of the fundamental constants. We determined the value of the fundamental constants combinations $${R}_{\infty }{m}_{{\rm{e}}}({m}_{{\rm{p}}}^{-1}+{m}_{{\rm{d}}}^{-1})$$ and mp/me with a fractional uncertainty of 2 × 10−11, in agreement with, but more precise than, current Committee on Data for Science and Technology values. These results also provide strong evidence of the correctness of previous key high-precision measurements and a more than 20-fold stronger bound for a hypothetical fifth force between a proton and a deuteron. A rotational spectroscopy technique is improved and used on clusters of trapped molecular hydrogen ions to demonstrate excellent agreement with high-precision ab initio quantum theory and to determine fundamental constants.

Modified Structure of Protons and Neutrons in Correlated Pairs

Abstract: The atomic nucleus is made of protons and neutrons (nucleons), that are themselves composed of quarks and gluons. Understanding how the quark-gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding nucleons is an outstanding challenge. Although evidence for such modification, known as the EMC effect, was first observed over 35 years ago, there is still no generally accepted explanation of its cause. Recent observations suggest that the EMC effect is related to close-proximity Short Range Correlated (SRC) nucleon pairs in nuclei. Here we report the first simultaneous, high-precision, measurements of the EMC effect and SRC abundances. We show that the EMC data can be explained by a universal modification of the structure of nucleons in neutron-proton (np) SRC pairs and present the first data-driven extraction of this universal modification function. This implies that, in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have its quark structure distorted.

Reversible manipulation of the magnetic state in SrRuO3 through electric-field controlled proton evolution.

Abstract: Ionic substitution forms an essential pathway to manipulate the structural phase, carrier density and crystalline symmetry of materials via ion-electron-lattice coupling, leading to a rich spectrum of electronic states in strongly correlated systems. Using the ferromagnetic metal SrRuO3 as a model system, we demonstrate an efficient and reversible control of both structural and electronic phase transformations through the electric-field controlled proton evolution with ionic liquid gating. The insertion of protons results in a large structural expansion and increased carrier density, leading to an exotic ferromagnetic to paramagnetic phase transition. Importantly, we reveal a novel protonated compound of HSrRuO3 with paramagnetic metallic as ground state. We observe a topological Hall effect at the boundary of the phase transition due to the proton concentration gradient across the film-depth. We envision that electric-field controlled protonation opens up a pathway to explore novel electronic states and material functionalities in protonated material systems.

Two-photon frequency comb spectroscopy of atomic hydrogen

Abstract: We have performed two-photon ultraviolet direct frequency comb spectroscopy on the 1S-3S transition in atomic hydrogen to illuminate the so-called proton radius puzzle and to demonstrate the potential of this method. The proton radius puzzle is a significant discrepancy between data obtained with muonic hydrogen and regular atomic hydrogen that could not be explained within the framework of quantum electrodynamics. By combining our result [f1S-3S = 2,922,743,278,665.79(72) kilohertz] with a previous measurement of the 1S-2S transition frequency, we obtained new values for the Rydberg constant [R∞ = 10,973,731.568226(38) per meter] and the proton charge radius [rp = 0.8482(38) femtometers]. This result favors the muonic value over the world-average data as presented by the most recent published CODATA 2014 adjustment.

Unidirectional and Selective Proton Transport in Artificial Heterostructured Nanochannels with Nano-to-Subnano Confined Water Clusters

Abstract: The construction of biological proton channel analogues has attracted substantial interest owing to their wide potential in separation of ions, sensing, and energy conversion. Here, metal-organic framework (MOF)/polymer heterogeneous nanochannels are presented, in which water molecules are confined to disordered clusters in the nanometer-sized polymer regions and to ordered chains with unique molecular configurations in the 1D sub-1-nm porous MOF regions, to realize unidirectional, fast, and selective proton transport properties, analogous to natural proton channels. Given the nano-to-subnano confined water junctions, experimental proton conductivities in the polymer-to-MOF direction of the channels are much higher than those in the opposite direction, showing a high rectification up to 500 and one to two orders of magnitude enhancement compared to the conductivity of proton transport in bulk water. The channels also show a good proton selectivity over other cations. Theoretical simulations further reveal that the preferential and fast proton conduction in the nano-to-subnano channel direction is attributed to extremely low energy barriers for proton transport from disordered to ordered water clusters. This study opens a novel approach to regulate ion permeability and selectivity of artificial ion channels.

Nanoscale percolation in doped BaZrO 3 for high proton mobility

Abstract: Acceptor-doped barium zirconate is a promising proton-conducting oxide for various applications, for example, electrolysers, fuel cells or methane-conversion cells. Despite many experimental and theoretical investigations there is, however, only a limited understanding as to how to connect the complex microscopic proton motion and the macroscopic proton conductivity for the full range of acceptor levels, from diluted acceptors to concentrated solid solutions. Here we show that a combination of density functional theory calculations and kinetic Monte Carlo simulations enables this connection. At low concentrations, acceptors trap protons, which results in a decrease of the average proton mobility. With increasing concentration, however, acceptors form nanoscale percolation pathways with low proton migration energies, which leads to a strong increase of the proton mobility and conductivity. Comparing our simulated proton conductivities with experimental values for yttrium-doped barium zirconate yields excellent agreement. We then predict that ordered dopant structures would not only strongly enhance the proton conductivities, but would also enable one- or two-dimensional proton conduction in barium zirconate. Finally, we show how the properties of other dopants influence the proton conductivity. Although acceptor-doped barium zirconate is a promising conductor for electrolysers or fuel cells, our understanding of the relationship between proton motion and conductivity is limited. Our simulations now suggest a generic nanoscale percolation mechanism for high mobility in other oxides.

Newly developed tellurium oxide glasses for nuclear shielding applications: An extended investigation

Abstract: Newly developed glasses were produced using different compositions as follows (in wt.%): (85TeO2-15ZnO, 85.00TeO2-12.95ZnO-2.05Al2O3, 85.40TeO2–3.20PbO-6.97ZnO-4.43Na2O, 83.5TeO2-16.5BaO, 82.77TeO2–17.23Nb2O5, 54.6TeO2-22.6WO3-22.8Bi2O3). The acquired mass attenuation coefficients (μ/ρ) were used to determine another vital parameters for gamma-ray shielding performance namely mean free path (MFP), half value layer (HVL), tenth value layer (TVL), energy absorption buildup factor (EABF), exposure buildup factor (EBF), effective atomic number (Zeff), respectively. Simultaneously, effective removal cross section (∑R) values for fast neutrons, proton projected range (PPR), alpha projected range (APR), proton mass stopping power (PMSP), alpha mass stopping power (AMSP), neutron absorption parameters (absorption neutron scattering cross section (σabs)), SAFE factors and relative dose distribution (RDD) have been investigated for fabricated glass samples. The results showed that the 54.6TeO2-22.6WO3-22.8Bi2O3 composition has the best performance in terms of nuclear shielding purposes. It is worth recommending the continuous investigations on chemical combinations and changes of TeO2 concentration for future applications.

Extraction of the Neutron Charge Radius from a Precision Calculation of the Deuteron Structure Radius.

Abstract: We present a high-accuracy calculation of the deuteron structure radius in chiral effective field theory. Our analysis employs the state-of-the-art semilocal two-nucleon potentials and takes into account two-body contributions to the charge density operators up to fifth order in the chiral expansion. The strength of the fifth-order short-range two-body contribution to the charge density operator is adjusted to the experimental data on the deuteron charge form factor. A detailed error analysis is performed by propagating the statistical uncertainties of the low-energy constants entering the two-nucleon potentials and by estimating errors from the truncation of the chiral expansion as well as from uncertainties in the nucleon form factors. Using the predicted value for the deuteron structure radius together with the very accurate atomic data for the difference of the deuteron and proton charge radii we, for the first time, extract the charge radius of the neutron from light nuclei. The extracted value reads ${r}_{n}^{2}=\ensuremath{-}{0.106}_{\ensuremath{-}0.005}^{+0.007}\text{ }\text{ }{\mathrm{fm}}^{2}$ and its magnitude is about $1.7\ensuremath{\sigma}$ smaller than the current value given by the Particle Data Group. In addition, given the high accuracy of the calculated deuteron charge form factor and its careful and systematic error analysis, our results open the way for an accurate determination of the nucleon form factors from elastic electron-deuteron scattering data measured at the Mainz Microtron and other experimental facilities.

Bi2O3 effect on physical, optical, structural and radiation safety characteristics of B2O3[sbnd]Na2O-ZnO[sbnd]CaO glass system

Abstract: Novel transparent glasses with nominal composition of 50B2O3 +15Na2O+15ZnO+(20−x)CaO+xBi2O3; x = 0, 5, 10, 15, and 20 were synthesized using melt quenching method. The molar volume and density of the produced glasses with boosting the substitution ratio of Bi2O3 were measured. X-ray diffraction (XRD) patterns of the glasses were obtained for confirming their amorphous structure. UV–Vis spectra of the prepared samples were detected over the range of 190–1100 nm. By using UV–Vis results, Fermi level energy (Ef), refractive index (n), optical energy gap (Eg), Urbach's energy (Eu), and optical dispersion parameters were estimated. Results exposed that the optical energy gap (Eg) and single-oscillator energy (Eo) were decreased however other parameters increased with increasing Bi2O3 content. Mass attenuation coefficient (μ/ρ), as an essential variable for photon protecting research, was attained at 0.015–15 MeV photon energies for investigated glasses. Other relevant variables that can define the photon protecting features like Mean Free Path (MFP), Half Value Layer (HVL), equivalent atomic number (Zeq), gamma-ray exposure buildup factor (EBF), energy-absorption buildup factor (EABF) were obtained for the prepared glasses. The corollaries revealed that the BCNZB20.0 glass can be a strong shield material against gamma radiation. Finally, the proficiency of proposed glasses to stop fast neutrons charged alpha and proton particles was explored utilizing effective removal cross section (ΣR) and Mass Stopping Power (MSP) parameters. The glass with 20% Bi2O3 (BCNZB20.0) addition is very effective in preventing charged and uncharged particles. The addition of Bi2O3 to the studied glass system not only improved the optical and structural features but also the nuclear radiation shielding properties.

Proton number fluctuations in $\sqrt{s_{NN}}$ = 2.4 GeV Au+Au collisions studied with HADES

Abstract: We present an analysis of proton number fluctuations in $\sqrt{s_{NN}}$ = 2.4 GeV Au+Au collisions measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI. With the help of extensive detector simulations done with IQMD transport model events including nuclear clusters, various nuisance effects influencing the observed proton cumulants have been investigated. Acceptance and efficiency corrections have been applied as a function of fine grained rapidity and transverse momentum bins, as well as considering local track density dependencies. Next, the effects of volume changes within particular centrality selections have been considered and beyond-leading-order corrections have been applied to the data. The efficiency and volume corrected proton number moments and cumulants Kn of orders n = 1, . . . , 4 have been obtained as a function of centrality and phase-space bin, as well as the corresponding correlators C_n . We find that the observed correlators show a power-law scaling with the mean number of protons, i.e. $C_n \propto ^n$, indicative of mostly long-range multi-particle correlations in momentum space. We also present a comparison of our results with Au+Au collision data obtained at RHIC at similar centralities, but higher $\sqrt{s_{NN}}$.

Review of proton and nuclear shape fluctuations at high energy.

Abstract: Determining the inner structure of protons and nuclei in terms of their fundamental constituents has been one of the main tasks of high energy nuclear and particle physics experiments. This quest started as a mapping of the (average) parton densities as a function of longitudinal momentum fraction and resolution scale. Recently, the field has progressed to more differential imaging, where one important development is the description of the event-by-event quantum fluctuations in the wave function of the colliding hadron. In this review, recent developments on the extraction of proton and nuclear transverse geometry with event-by-event fluctuations from collider experiments at high energy is presented. The importance of this fundamentally interesting physics in other collider experiments like in studies of the properties of the quark gluon plasma is also illustrated.

Nuclear Quantum Effects Largely Influence Molecular Dissociation and Proton Transfer in Liquid Water under an Electric Field.

Abstract: Proton transfer in liquid water controls acid-base chemistry, crucial enzyme reactions, and the functioning of fuel cells. Externally applied static electric fields in water are capable of dissociating molecules and transferring protons across the H-bond network. However, the impact of nuclear quantum effects (NQEs) on these fundamental field-induced phenomena has not yet been reported. By comparing state-of-the-art ab initio molecular dynamics (AIMD) and path integral AIMD simulations of water under electric fields, I show that quantum delocalization of the proton lowers the molecular ionization threshold to approximately one-third. Moreover, also the water behavior as a protonic semiconductor is considerably modified by the inclusion of NQEs. In fact, when the quantum nature of the nuclei is taken into account, the proton conductivity is ∼50% larger. This work proves that NQEs sizably affect the protolysis phenomenon and proton transfer in room-temperature liquid water.

Search for millicharged particles in proton-proton collisions at s =13 TeV

Abstract: We report on a search for elementary particles with charges much smaller than the electron charge using a data sample of proton-proton collisions provided by the CERN Large Hadron Collider in 2018, corresponding to an integrated luminosity of 37.5 fb$^{-1}$ at a center-of-mass energy of 13 TeV. A prototype scintillator-based detector is deployed to conduct the first search at a hadron collider sensitive to particles with charges ${\leq}0.1e$. The existence of new particles with masses between 20 and 4700 MeV is excluded at 95% confidence level for charges between $0.006e$ and $0.3e$, depending on their mass. New sensitivity is achieved for masses larger than $700$ MeV.

High-current stream of energetic α particles from laser-driven proton-boron fusion.

Abstract: The nuclear reaction known as proton-boron fusion has been triggered by a subnanosecond laser system focused onto a thick boron nitride target at modest laser intensity (∼10^{16}W/cm^{2}), resulting in a record yield of generated α particles. The estimated value of α particles emitted per laser pulse is around 10^{11}, thus orders of magnitude higher than any other experimental result previously reported. The accelerated α-particle stream shows unique features in terms of kinetic energy (up to 10 MeV), pulse duration (∼10 ns), and peak current (∼2 A) at 1 m from the source, promising potential applications of such neutronless nuclear fusion reactions. We have used a beam-driven fusion scheme to explain the total number of α particles generated in the nuclear reaction. In this model, protons accelerated inside the plasma, moving forward into the bulk of the target, can interact with ^{11}B atoms, thus efficiently triggering fusion reactions. An overview of literature results obtained with different laser parameters, experimental setups, and target compositions is reported and discussed.

The proton size

Abstract: The proton charge radius has been measured since the 1950s using elastic electron–proton scattering and ordinary hydrogen atomic spectroscopy. In 2010, a highly precise measurement of the proton charge radius using, for the first time, muonic hydrogen spectroscopy unexpectedly led to controversy, as the value disagreed with the previously accepted one. Since then, atomic and nuclear physicists have been trying to understand this discrepancy by checking theories, questioning experimental methods and performing new experiments. Recently, two measurements from electron scattering and ordinary hydrogen spectroscopy were found to agree with the results from muonic atom spectroscopy. Is the ‘proton-radius puzzle’ now resolved? In this Review, we scrutinize the experimental studies of the proton radius to gain insight on this issue. We provide a brief history of the proton before describing the techniques used to measure its radius and the current status of the field. We assess the precision and reliability of available experimental data, with particular focus on the most recent results. Finally, we discuss the forthcoming new generation of refined experiments and theoretical calculations that aim to definitely end the debate on the proton size. The charge radius of the proton is controversial because measurements by different methods disagree. Recent results indicate that these measurements might be reconciled. In this Review, we discuss the experimental techniques used to measure the proton radius and describe the current status of the field as well as forthcoming experiments.

Production cross-sections of Mo-isotopes induced by fast neutrons based on the 9Be(p, n) reaction

Abstract: We measured the flux-weighted average cross-sections of the 100Mo(n, 2n)99Mo and 92Mo(n, 3n)90Mo reactions with the average neutron energies between 14.0- and 31.8-MeV by using an activation and off-line γ-ray spectrometric technique. The fast neutrons were generated based on the 9Be(p, n) reaction with the proton energies of 25-, 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron flux was measured by using the 27Al(n, α)24Na monitor reaction, whereas the neutron spectra were simulated by using the MCNPX 2.6.0 code. The theoretical cross-sections of the 100Mo(n, 2n)99Mo and 92Mo(n, xn)91.90,89Mo reactions as a function of mono-energetic neutron were calculated by using the TALYS-1.9 code. The present results for the 100Mo(n, 2n)99Mo and 92Mo(n, 3n)90Mo reactions are compared with the calculated neutron flux-weighted average values based on the literature data and theoretical cross-sections as a function of mono-energetic neutron energy, and show a good agreement.

Tuning proton dissociation energy in proton carrier doped 2D covalent organic frameworks for anhydrous proton conduction at elevated temperature

Abstract: A theoretical and experimental study gives insights into the change of proton dissociation energy of anhydrous proton carriers (phosphoric acid and 1,2,4-triazole) doped in 2D covalent organic frameworks (COFs) with neutral, polar, Lewis base and positively charged sites in their 1D channels. The dielectric properties of proton carrier incorporated COFs were investigated to determine the formation of nanoscale ionic phases in COFs' channels. The proton carrier doped cationic COF exhibits a much higher dielectric constant in the frequency range of 103 Hz to 107 Hz than other doped COFs, which may arise from the formation of ethidium-biphosphate or ethidium-triazole ion-pairs in charged COF channels. The ion-pairs lined along cationic COFs' channels produce an enhanced proton dissociation degree coupled with a high dielectric response, leading to a new proton conductivity record (2.77 × 10−2 S cm−1) set by the cationic COF among all reported porous materials under anhydrous conditions and elevated temperatures.

Direct observation of water-mediated single-proton transport between hBN surface defects

Abstract: Aqueous proton transport at interfaces is ubiquitous and crucial for a number of fields, ranging from cellular transport and signalling, to catalysis and membrane science. However, due to their light mass, small size and high chemical reactivity, uncovering the surface transport of single protons at room temperature and in an aqueous environment has so far remained out-of-reach of conventional atomic-scale surface science techniques, such as scanning tunnelling microscopy. Here, we use single-molecule localization microscopy to resolve optically the transport of individual excess protons at the interface of hexagonal boron nitride crystals and aqueous solutions at room temperature. Single excess proton trajectories are revealed by the successive protonation and activation of optically active defects at the surface of the crystal. Our observations demonstrate, at the single-molecule scale, that the solid/water interface provides a preferential pathway for lateral proton transport, with broad implications for molecular charge transport at liquid interfaces. Super-resolution microscopy of defects in a two-dimensional material unveils the transport of single proton charges at solid/water interfaces.

Eppur si Muove: Proton Diffusion in Halide Perovskite Single Crystals.

Abstract: Ion diffusion affects the optoelectronic properties of halide-perovskites (HaPs). Until now, the fastest diffusion has been attributed to the movement of the halides, largely neglecting the contribution of protons, on the basis of computed density estimates. Here, the process of proton diffusion inside HaPs, following deuterium-hydrogen exchange and migration in MAPbI3 , MAPbBr3 , and FAPbBr3 single crystals, is proven through D/H NMR quantification, Raman spectroscopy, and elastic recoil detection analysis, challenging the original assumption of halide-dominated diffusion. The results are confirmed by impedance spectroscopy, where MAPbBr3 - and CsPbBr3 -based solar cells respond at very different frequencies. Water plays a key role in allowing the migration of protons as deuteration is not detected in its absence. The water contribution is modeled to explain and forecast its effect as a function of its concentration in the perovskite structure. These findings are of great importance as they evidence how unexpected, water-dependent proton diffusion can be at the basis of the ≈7 orders of magnitude spread of diffusion (attributed to I- and Br- ) coefficient values, reported in the literature. The reported enhancement of the optoelectronic properties of HaP when exposed to small amounts of water may be related to the finding.

Cryo-EM and MD infer water-mediated proton transport and autoinhibition mechanisms of Vo complex.

Abstract: Rotary vacuolar adenosine triphosphatases (V-ATPases) drive transmembrane proton transport through a Vo proton channel subcomplex. Despite recent high-resolution structures of several rotary ATPases, the dynamic mechanism of proton pumping remains elusive. Here, we determined a 2.7-A cryo–electron microscopy (cryo-EM) structure of yeast Vo proton channel in nanodisc that reveals the location of ordered water molecules along the proton path, details of specific protein-lipid interactions, and the architecture of the membrane scaffold protein. Moreover, we uncover a state of Vo that shows the c-ring rotated by ~14°. Molecular dynamics simulations demonstrate that the two rotary states are in thermal equilibrium and depict how the protonation state of essential glutamic acid residues couples water-mediated proton transfer with c-ring rotation. Our cryo-EM models and simulations also rationalize a mechanism for inhibition of passive proton transport as observed for free Vo that is generated as a result of V-ATPase regulation by reversible disassembly in vivo.

Sulfonated Sub-1-nm Metal-Organic Framework Channels with Ultrahigh Proton Selectivity.

Abstract: Biological proton channels are sub-1-nm protein pores with ultrahigh proton (H+) selectivity over other ions. Inspired by biological proton channels, developing artificial proton channels with biol...

Newly developed Zinc-Tellurite glass system: An experimental investigation on impact of Ta2O5 on nuclear radiation shielding ability

Abstract: In this paper, the nuclear shielding properties of newly fabricated Zinc-Tellurite glasses doped with Ta2O5 with a composition (25ZnO.75TeO2)100-x.(Ta2O5)x (x=0, 1, 2, 3 mol%) were studied. Ta2O5 doped Zinc-Tellurite glasses prepared by the traditional melt quenching method. The mass attenuation coefficients were achieved for prepared glasses at 0.081-0.383 MeV photon energies employing experimental transmission measurements, which were performed with 3 Ci Ba-133 point source and Ultra Ge detector. The experimental results were compared with simulated MCNPX and theoretical WinXCOM data. Moreover, another important nuclear shielding parameters such as mass attenuation coefficient, half value layer, effective atomic number, effective electron density, equivalent atomic numbers, alpha and proton projected ranges, mass stopping power in the protection of gamma, neutron, alpha and proton radiation were calculated. In addition, buildup factors of investigated glasses were determined by using the G-P fitting method. Moreover, effective removal cross section ΣR and transition factors were determined. According to the results, the addition of Ta2O5 to the glass samples has a positive effect on the performance of nuclear shielding effects of the glass samples. It can be concluded that ZTT3 glass sample with the highest Ta2O5 contribution has excellent nuclear radiation shielding ability among the other fabricated glass samples.

Hydrogen Portal to Exotic Radioactivity.

Abstract: We show that in a special class of dark sector models, the hydrogen atom can serve as a portal to new physics, through its decay occurring in abundant populations in the Sun and on Earth The large fluxes of hydrogen decay daughter states can be detected via their decay or scattering By constructing two models for either detection channel, we show that the recently reported excess in electron recoils at xenon1t could be explained by such signals in large regions of parameter space unconstrained by proton and hydrogen decay limits

First Measurement of Differential Charged Current Quasielasticlike νμ -Argon Scattering Cross Sections with the MicroBooNE Detector

Abstract: We report on the first measurement of flux-integrated single differential cross sections for charged-current (CC) muon neutrino (ν_{μ}) scattering on argon with a muon and a proton in the final state, ^{40}Ar (ν_{μ},μp)X. The measurement was carried out using the Booster Neutrino Beam at Fermi National Accelerator Laboratory and the MicroBooNE liquid argon time projection chamber detector with an exposure of 4.59×10^{19} protons on target. Events are selected to enhance the contribution of CC quasielastic (CCQE) interactions. The data are reported in terms of a total cross section as well as single differential cross sections in final state muon and proton kinematics. We measure the integrated per-nucleus CCQE-like cross section (i.e., for interactions leading to a muon, one proton, and no pions above detection threshold) of (4.93±0.76_{stat}±1.29_{sys})×10^{-38} cm^{2}, in good agreement with theoretical calculations. The single differential cross sections are also in overall good agreement with theoretical predictions, except at very forward muon scattering angles that correspond to low-momentum-transfer events.

Measurement of differential cross sections for νμ -Ar charged-current interactions with protons and no pions in the final state with the MicroBooNE detector

Abstract: We present an analysis of MicroBooNE data with a signature of one muon, no pions, and at least one proton above a momentum threshold of 300 MeV/c (CC0$\pi$Np). This is the first differential cross section measurement of this topology in neutrino-argon interactions. We achieve a significantly lower proton momentum threshold than previous carbon and scintillator-based experiments. Using data collected from a total of approximately $1.6 \times 10^{20}$ protons-on-target, we measure the muon neutrino cross section for the CC0$\pi$Np interaction channel in argon at MicroBooNE in the Booster Neutrino Beam which has a mean energy of around 800 MeV. We present the results from a data sample with estimated efficiency of 29\% and purity of 76\% as differential cross sections in five reconstructed variables: the muon momentum and polar angle, the leading proton momentum and polar angle, and the muon-proton opening angle. We include smearing matrices that can be used to "forward-fold" theoretical predictions for comparison with these data. We compare the measured differential cross sections to a number of recent theory predictions demonstrating largely good agreement with this first-ever data set on argon.

Three hydrogen-bonded organic frameworks with water-induced single-crystal-to-single-crystal transformation and high proton conductivity

Abstract: In the development of proton conductors, it is very important to increase the density of proton carriers to adjust proton conduction pathways. In this work, two novel isomeric hydrogen-bonded organ...