Search

This paper reports the track multiplicity and kinematics of muons, charged pions, and protons from charged-current inclusive $\bar{\nu}_{\mu}$ and $\nu_{\mu}$ interactions on a water target, measured using a nuclear emulsion detector in the NINJA experiment. A 3-kg water target was exposed to the T2K antineutrino-enhanced beam with a mean energy of 1.3 GeV. Owing to the high-granularity of the nuclear emulsion, protons with momenta down to 200 MeV/$c$ from the neutrino-water interactions were detected. We find good agreement between the observed data and model predictions for all kinematic distributions other than the number of charged pions. These results demonstrate the capability of measurements with nuclear emulsion to improve neutrino interaction models., Comment: 22 pages, 20 figures

Charge acceleration during an intense light field application to solids attracts much attention as elementary processes in high-harmonic generation and photoelectron emission [1-7]. For manipulating such attosecond dynamics of charge, carrier-envelope-phase (CEP:relative phase between carrier oscillation of light field and its envelope function) control has been employed in insulators, nanometal and graphene [8-10]. In superconducting materials, collective control of charge motion is expected because of its strongly coherent nature of quasi-particles. Here, in a layered organic superconductor, second harmonic generation (SHG) is observed by using a single-cycle 6 femtosecond near infrared pulse, which is in contrast to the common belief that even harmonics are forbidden in the centrosymmetric system. The SHG shows a CEP sensitive nature and an enhancement near the superconducting temperature. The result and its quantum many-body analysis indicate that a polarized current is induced by non-dissipative acceleration of charge, which is amplified by superconducting fluctuations. This will lead to petahertz functions of superconductors and of strongly correlated systems., Comment: Anotherversion hase been accepted in Nature communications

The forward Compton amplitude describes the process of virtual photon scattering from a hadron and provides an essential ingredient for the understanding of hadron structure. As a physical amplitude, the Compton tensor naturally includes all target mass corrections and higher twist effects at a fixed virtuality, $Q^2$. By making use of the second-order Feynman-Hellmann theorem, the nucleon Compton tensor is calculated in lattice QCD at an unphysical quark mass across a range of photon momenta $3 \lesssim Q^2 \lesssim 7$ GeV$^2$. This allows for the $Q^2$ dependence of the low moments of the nucleon structure functions to be studied in a lattice calculation for the first time. The results demonstrate that a systematic investigation of power corrections and the approach to parton asymptotics is now within reach., Comment: 18 pages, 8 figures. Title has been changed due to the Editor's request. Version to appear in PRD

Motivated by the detection of a significant dipole structure in the arrival directions of ultrahigh-energy cosmic rays above 8 EeV reported by the Pierre Auger Observatory (Auger), we search for a large-scale anisotropy using data collected with the surface detector array of the Telescope Array Experiment (TA). With 11 years of TA data, a dipole structure in a projection of the right ascension is fitted with an amplitude of 3.3+- 1.9% and a phase of 131 +- 33 degrees. The corresponding 99% confidence-level upper limit on the amplitude is 7.3%. At the current level of statistics, the fitted result is compatible with both an isotropic distribution and the dipole structure reported by Auger., Comment: 6 pages, 3 figures, 1 table, Proofed title. Added journal reference and DOI

Ultra high energy cosmic rays provide the highest known energy source in the universe to measure proton cross sections. Though conditions for collecting such data are less controlled than an accelerator environment, current generation cosmic ray observatories have large enough exposures to collect significant statistics for a reliable measurement for energies above what can be attained in the lab. Cosmic ray measurements of cross section use atmospheric calorimetry to measure depth of air shower maximum ($X_{\mathrm{max}}$), which is related to the primary particle's energy and mass. The tail of the $X_{\mathrm{max}}$ distribution is assumed to be dominated by showers generated by protons, allowing measurement of the inelastic proton-air cross section. In this work the proton-air inelastic cross section measurement, $\sigma^{\mathrm{inel}}_{\mathrm{p-air}}$, using data observed by Telescope Array's Black Rock Mesa and Long Ridge fluorescence detectors and surface detector array in hybrid mode is presented. $\sigma^{\mathrm{inel}}_{\mathrm{p-air}}$ is observed to be $520.1 \pm 35.8$[Stat.] $^{+25.0}_{-40}$[Sys.]~mb at $\sqrt{s} = 73$ TeV. The total proton-proton cross section is subsequently inferred from Glauber formalism and is found to be $\sigma^{\mathrm{tot}}_{\mathrm{pp}} = 139.4 ^{+23.4}_{-21.3}$ [Stat.]$ ^{+15.0}_{-24.0}$[Sys.]~mb.

Evidence for a large-scale supergalactic cosmic ray multiplet (arrival directions correlated with energy) structure is reported for ultra-high energy cosmic ray (UHECR) energies above 10$^{19}$ eV using seven years of data from the Telescope Array (TA) surface detector and updated to 10 years. Previous energy-position correlation studies have made assumptions regarding magnetic field shapes and strength, and UHECR composition. Here the assumption tested is that, since the supergalactic plane is a fit to the average matter density of the local Large Scale Structure (LSS), UHECR sources and intervening extragalactic magnetic fields are correlated with this plane. This supergalactic deflection hypothesis is tested by the entire field-of-view (FOV) behavior of the strength of intermediate-scale energy-angle correlations. These multiplets are measured in spherical cap section bins (wedges) of the FOV to account for coherent and random magnetic fields. The structure found is consistent with supergalactic deflection, the previously published energy spectrum anisotropy results of TA (the hotspot and coldspot), and toy-model simulations of a supergalactic magnetic sheet. The seven year data post-trial significance of this supergalactic structure of multiplets appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be 4.2$\sigma$. The ten years of data post-trial significance is 4.1$\sigma$. Furthermore, the starburst galaxy M82 is shown to be a possible source of the TA Hotspot, and an estimate of the supergalactic magnetic field using UHECR measurements is presented.

Systems with the quantum numbers of up to twelve charged and neutral pseudoscalar mesons, as well as one-, two-, and three-nucleon systems, are studied using dynamical lattice quantum chromodynamics and quantum electrodynamics (QCD+QED) calculations and effective field theory. QED effects on hadronic interactions are determined by comparing systems of charged and neutral hadrons after tuning the quark masses to remove strong isospin breaking effects. A non-relativistic effective field theory, which perturbatively includes finite-volume Coulomb effects, is analyzed for systems of multiple charged hadrons and found to accurately reproduce the lattice QCD+QED results. QED effects on charged multi-hadron systems beyond Coulomb photon exchange are determined by comparing the two- and three-body interaction parameters extracted from the lattice QCD+QED results for charged and neutral multi-hadron systems., Comment: 67 pages, 29 figures. Published version

Computing the gluon component of momentum in the nucleon is a difficult and computationally expensive problem, as the matrix element involves a quark-line-disconnected gluon operator which suffers from ultra-violet fluctuations. But also necessary for a successful determination is the non-perturbative renormalisation of this operator. As a first step we investigate here this renormalisation in the RI-MOM scheme. Using quenched QCD as an example, a statistical signal is obtained in a direct calculation using an adaption of the Feynman-Hellmann technique., Comment: 7 pages, Proceedings of the 37th Annual International Symposium on Lattice Field Theory (Lattice 2019), 16-22 June 2019, Wuhan, China

The seminal theoretical works of Berezinskii, Kosterlitz, and Thouless presented a new paradigm for phase transitions in condensed matter that are driven by topological excitations. These transitions have been extensively studied in the context of two-dimensional XY models -- coupled compasses -- and have generated interest in the context of quantum simulation. Here, we use a circuit quantum-electrodynamics architecture to study the critical behavior of engineered XY models through their dynamical response. In particular, we examine not only the unfrustrated case but also the fully-frustrated case which leads to enhanced degeneracy associated with the spin rotational [U$(1)$] and discrete chiral ($Z_2$) symmetries. The nature of the transition in the frustrated case has posed a challenge for theoretical studies while direct experimental probes remain elusive. Here we identify the transition temperatures for both the unfrustrated and fully-frustrated XY models by probing a Josephson junction array close to equilibrium using weak microwave excitations and measuring the temperature dependence of the effective damping obtained from the complex reflection coefficient. We argue that our probing technique is primarily sensitive to the dynamics of the U$(1)$ part., Comment: 10 pages, 7 figures

The partonic structure of hadrons plays an important role in a vast array of high-energy and nuclear physics experiments. It also underpins the theoretical understanding of hadron structure. Recent developments in lattice QCD offer new opportunities for reliably studying partonic structure from first principles. Here we report on the use of the Feynman-Hellmann theorem to study the forward Compton amplitude in the unphysical region. We demonstrate how this amplitude provides direct constraint on hadronic inelastic structure functions. The use of external momentum transfer allows us to study the $Q^2$ evolution to explore the onset of asymptotic scaling and reveal higher-twist effects in partonic structure., Comment: 7 pages, 5 figures; presented at the 37th International Symposium on Lattice Field Theory (Lattice2019), 16-22 June 2019, Wuhan, China

The strong coupling constant $1/g^2$ and the vacuum angle $\theta$ of the SU(3) Yang-Mills theory are investigated in the infrared limit under the renormalization group flow. It is shown that the theory has an infrared attractive fixed point at $1/g^2 = \theta = \,0$, which leads to linear confinement and naturally solves the strong CP problem. In particular, any initial value of $\theta \neq 0$ is found to be driven to $\theta = 0$ at macroscopic distances, where quarks and gluons freeze into hadrons by the confinement mechanism., Comment: 7 pages, 9 figures, talk at Lattice2019, typos corrected

Mixing in the $\Sigma^0$-$\Lambda^0$ system is a direct consequence of broken isospin symmetry and is a measure of both isospin-symmetry breaking as well as general SU(3)-flavour symmetry breaking. In this work we present a new scheme for calculating the extent of $\Sigma^0$-$\Lambda^0$ mixing using simulations in lattice QCD+QED and perform several extrapolations that compare well with various past determinations. Our scheme allows us to easily contrast the QCD-only mixing case with the full QCD+QED mixing., Comment: 9 pages, 3 figures

By considering a flavour expansion about the SU(3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU(3) is broken by the mass difference between quarks. Similarly to hadron masses we find the expansions to be constrained along a mass trajectory where the singlet quark mass is held constant, which provides invaluable insight into the mechanism of flavour symmetry breaking and proves beneficial for extrapolations to the physical point. Expansions are given up to third order in the expansion parameters. Considering higher orders would give no further constraints on the expansion parameters. The relation of the expansion coefficients to the quark-line-connected and quark-line disconnected terms in the 3-point correlation functions is also given. As we consider Wilson clover-like fermions, the addition of improvement coefficients is also discussed and shown to be included in the formalism developed here. As an example of the method we investigate this numerically via a lattice calculation of the flavour-conserving matrix elements of the vector first class form factors., Comment: 70 pages. Small additions and corrections. Published version

We investigate the finite size effect on the vector meson and the baryon sectors using a subset of the "PACS10" configurations which are generated, keeping the space-time volumes over (10 fm$)^4$ in 2+1 flavor QCD at the physical point. Comparing the results on (5.5 fm$)^4$ and (10.9 fm$)^4$ lattices the ground states of octet baryons , which are stable on the lattice, show no finite size effect within less than 0.5% level of statistical errors. For those of vector mesons, which are unstable on the lattice, we observe that the effective masses are well below the experimental resonance levels both on (5.5 fm$)^4$ and (10.9 fm$)^4$ lattices. For the decuplet baryon sector we have found that the time dependence of the effective mass looks quite similar to that for the vector meson sector including the $\Omega$ baryon channel. We discuss its origin due to a possible mixing with the nearby multihadron states. Since the $\Xi$ baryon mass can be determined with the smallest ambiguity among the vector meson and the baryon masses, we use it together with the pion and kaon masses as the physical inputs to determine the physical point., Comment: 9 pages, 8 figures: published version

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies $E>100$ TeV. As a result, we observed 24 photon-like events with $E>100$ TeV against 5.5 background events, which corresponds to 5.6$\sigma$ statistical significance. This is the first detection of photons with $E>100$ TeV from an astrophysical source., Comment: April 4, 2019; Submitted to the Physical Review Letters

Brillouin light scattering in ferromagnetic materials usually involves one magnon and two photons and their total angular momentum is conserved. Here, we experimentally demonstrate the presence of a helicity-changing two-magnon Brillouin light scattering in a ferromagetic crystal, which can be viewed as a four-wave mixing process involving two magnons and two photons. Moreover, we observe an unconventional helicity-changing one-magnon Brillouin light scattering, which apparently infringes the conservation law of the angular momentum. We show that the crystal angular momentum intervenes to compensate the missing angular momentum in the latter scattering process., Comment: 14 pages, 6 figures

We report a new analysis of the isospin splittings within the decuplet baryon spectrum. Our numerical results are based upon five ensembles of dynamical QCD+QED lattices. The analysis is carried out within a flavour-breaking expansion which encodes the effects of breaking the quark masses and electromagnetic charges away from an approximate SU(3) symmetric point. The results display total isospin splittings within the approximate SU(2) multiplets that are compatible with phenomenological estimates. Further, new insight is gained into these splittings by separating the contributions arising from strong and electromagnetic effects. We also present an update of earlier results on the octet baryon spectrum., Comment: 17 pages, 7 tables, 5 figures. Version accepted for publication in J.Phys.G

The current $3.5\sigma$ discrepancy between experimental and Standard Model determinations of the anomalous magnetic moment of the muon $a_\mu=(g-2)/2$ can only be extended to the discovery $5\sigma$ regime through a reduction of both experimental and theoretical uncertainties. On the theory side, this means a determination of the hadronic vacuum polarisation (HVP) contribution to better than 0.5%, a level of precision that demands the inclusion of QCD + QED effects to properly understand how the behaviour of quarks are modified when their electric charges are turned on. The QCDSF collaboration has generated an ensemble of configurations with dynamical QCD and QED fields with the specific aim of studying flavour breaking effects arising from differences in the quark masses and charges in physical quantities. Here we study these effects in a calculation of HVP around the SU(3) symmetric point. Furthermore, by performing partially-quenched simulations we are able to cover a larger range of quark masses and charges on these configurations and then fit the results to an SU(3) flavour breaking expansion. Subsequently, this allows for an extrapolation to the physical point., Comment: 7 pages, 6 figures, conference proceedings for talk presented at the 36th Annual International Symposium on Lattice Field Theory, 22-28 July 2018, Michigan State University, East Lansing, Michigan, USA

Quantum communication protocols based on nonclassical correlations can be more efficient than known classical methods and offer intrinsic security over direct state transfer. In particular, remote state preparation aims at the creation of a desired and known quantum state at a remote location using classical communication and quantum entanglement. We present an experimental realization of deterministic continuous-variable remote state preparation in the microwave regime over a distance of 35 cm. By employing propagating two-mode squeezed microwave states and feedforward, we achieve the remote preparation of squeezed states with up to 1.6 dB of squeezing below the vacuum level. We quantify security in our implementation using the concept of the one-time pad. Our results represent a significant step towards microwave quantum networks between superconducting circuits., Comment: Main text: 6 pages, 4 figures; Supplementary Information: 8 pages, 5 figures

Quark line disconnected matrix elements of an operator, such as the axial current, are difficult to compute on the lattice. The standard method uses a stochastic estimator of the operator, which is generally very noisy. We discuss and develop further our alternative approach using the Feynman-Hellmann theorem which involves only evaluating two-point correlation functions. This is applied to computing the contribution of the quark spin to the nucleon and in particular for the strange quark. In this process we also pay particular attention to the development of an SU(3) flavour breaking expansion for singlet operators., Comment: 7 pages, Proceedings of the 36th International Symposium on Lattice Field Theory (Lattice 2018), July 22-28, 2018, East Lancing, USA

The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminium nucleus ($\mu-e$ conversion, $\mu^- N \to e^- N$); a lepton flavor violating process. The experimental sensitivity goal for this process in the Phase-I experiment is $3.1\times10^{-15}$, or 90 % upper limit of branching ratio of $7\times 10^{-15}$, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the \mue conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described., Comment: A minor correction applied in Eq. 3

We investigate the finite size effect on pseudoscalar meson masses and decay constants using a subset of the "PACS10" configurations which are generated keeping the space-time volumes over (10 fm$)^4$ in 2+1 flavor QCD at the physical point. We have tried two kinds of analyses, fixing $\kappa$ values or measured axial Ward identity quark masses. Comparing the results on (5.4 fm$)^4$ and (10.8 fm$)^4$ lattices, we have found a sizable finite size effect on the pseudoscalar meson sector in the former analysis: a 2.1(8)%, 4.8(1.6)%, and 0.36(31)% finite size effect on $m_\pi$, $m_{\rm ud}$, and $f_\pi$, respectively, on the (5.4 fm$)^4$ lattice. For the latter analysis, the finite size effect on the pseudoscalar meson decay constants is 0.66(33)% for $f_\pi$, 0.26(13)% for $f_K$, and 0.40(32)% for $f_K/f_\pi$. These values with two-sigma error bars are consistent with the predictions from the full one-loop SU(3) chiral perturbation theory, which are 0.20% for $f_\pi$, 0.08% for $f_K$, and 0.13% for $f_K/f_\pi$. The finite size effect on the pseudoscalar meson masses is hardly detected under the current statistical precision., Comment: 7 pages, 10 figures, published version

We examine the possible influence of Earth-directed coronal mass ejections (ECMEs) on the Sun's shadow in the 3~TeV cosmic-ray intensity observed by the Tibet-III air shower (AS) array. We confirm a clear solar-cycle variation of the intensity deficit in the Sun's shadow during ten years between 2000 and 2009. This solar-cycle variation is overall reproduced by our Monte Carlo (MC) simulations of the Sun's shadow based on the potential field model of the solar magnetic field averaged over each solar rotation period. We find, however, that the magnitude of the observed intensity deficit in the Sun's shadow is significantly less than that predicted by MC simulations, particularly during the period around solar maximum when a significant number of ECMEs is recorded. The $\chi^2$ tests of the agreement between the observations and the MC simulations show that the difference is larger during the periods when the ECMEs occur, and the difference is reduced if the periods of ECMEs are excluded from the analysis. This suggests the first experimental evidence of the ECMEs affecting the Sun's shadow observed in the 3~TeV cosmic-ray intensity., Comment: 11 pages, 3 figures, accepted for publication in the ApJ

Bose-Einstein condensation of alpha clusters in light and medium-heavy nuclei is studied in the frame of the field theoretical superfluid cluster model. The order parameter of the phase transition from the Wigner phase to the Nambu-Goldstone phase is a superfluid amplitude, square of the moduli of which is the superfluid density distribution. The zero mode operators due to the spontaneous symmetry breaking of the global phase in the finite number of alpha clusters are rigorously treated. The theory is systematically applied to N alpha nuclei from12C-52Fe at various condensation rates. In 12C it is found that the energy levels of the gas-like well-developed alpha cluster states above the Hoyle state are reproduced well in agreement with experiment for realistic condensation rates of alpha clusters. The electric E2 and E0 transitions are calculated and found to be sensitive to the condensation rates. The profound raison d'etre of the alpha cluster gas-like states above the Hoyle state, whose structure has been interpreted geometrically in the nuclear models without the order parameter such as the cluster models or ab initio calculations, is revealed. It is found that in addition to the Bogoliubov-de Gennes vibrational mode states collective states of the zero mode operators appear systematically at low excitation energies from the N alpha threshold energy. These collective states, new-type soft modes in nuclei due to the Bose-Einstein condensation of the alpha clusters, emerge systematically in light and medium-heavy mass regions and are also located at high excitation energies from the ground state in contrast to the traditional concept of soft mode in the low excitation energy region., Comment: 19 pages. 22 figures

A Charge eXchange Recombination Spectroscopy (CXRS) system designed to measure the poloidal rotation velocity is developed in Heliotron J. The poloidal CXRS system measures the carbon emission line (C VI, n=8-7, 529.05nm) and the Doppler shift of the emission line provides the information of plasma rotation velocity. A high throughput photographic-lens monochromator (F/2.8) with 0.73nm/mm dispersion is adopted to achieve high rotation velocity and temporal resolution. Since two heating neutral beams from two tangential injectors (NBI) are used as the diagnostic beams, a wide observation range (0.26 < 0.06) at peripheral region (r/a>0.6). The system design and the calibration method are presented. The initial results of poloidal rotation measurement show an electron diamagnetic rotation in an NBI heated plasma, while an ion diamagnetic rotation is observed when ECH is additionally applied. The evaluated radial electric field profile shows a positive Er at plasma core region in the ECH+NBI plasma, and a negative Er in the NBI heated plasma., Comment: With 20 pages, 10 figures

The axion is a hypothetical elementary particle postulated by the Peccei-Quinn theory to resolve the strong CP problem in QCD. If axions exist and have low mass, they are a candidate for dark matter as well. So far our knowledge of the properties of the QCD axion rests on semi-classical arguments and effective theory. In this work we perform, for the first time, a fully dynamical investigation of the Peccei-Quinn theory, focussing on the axion mass, by simulating the theory on the lattice. The results of the simulation are found to be in conflict with present axion phenomenology., Comment: 16 pages, 9 figures; theoretical considerations refined, numerical results on larger lattices added, text corrected and improved

Telescope Array (TA) is the largest experiment in the Northern Hemisphere studying ultrahigh energy cosmic rays. TA measurements of the cosmic ray spectrum using the surface detector have the best statistical power in the experiment, and observe the ankle of the spectrum and the high energy cutoff. When the data are divided into two declination bands, above and below 24.8 degrees, the cutoff appears at $10^{19.64 \pm 0.04}$ ($10^{19.84 \pm 0.02}$) eV in the lower (higher) band, an energy difference of 58\%. The global significance of the difference is 4.3 standard deviations. The lack of an instrumental cause of this difference implies it is astrophysical in nature.

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disc center in the "Away" ("Toward") IMF sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the "Away" ("Toward") sector is $1.54 \pm 0.21_{\rm stat} \pm 0.20_{\rm syst}$ ($1.62 \pm 0.15_{\rm stat} \pm 0.22_{\rm syst}$) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field., Comment: 7 pages, 4 figures

Magnetostatic modes supported by a ferromagnetic sphere have been known as the Walker modes, each of which possesses an orbital angular momentum as well as a spin angular momentum along a static magnetic field. The Walker modes with non-zero orbital angular momenta exhibit topologically non-trivial spin textures, which we call \textit{magnetic quasi-vortices}. Photons in optical whispering gallery modes supported by a dielectric sphere possess orbital and spin angular momenta forming \textit{optical vortices}. Within a ferromagnetic, as well as dielectric, sphere, two forms of vortices interact in the process of Brillouin light scattering. We argue that in the scattering there is a selection rule that dictates the exchange of orbital angular momenta between the vortices. The selection rule is shown to be responsible for the experimentally observed nonreciprocal Brillouin light scattering., Comment: 7 pages, 4 figures

A ferromagnetic sphere can support \textit{optical vortices} in forms of whispering gallery modes and \textit{magnetic quasi-vortices} in forms of magnetostatic modes with non-trivial spin textures. These vortices can be characterized by their orbital angular momenta. We experimentally investigate Brillouin scattering of photons in the whispering gallery modes by magnons in the magnetostatic modes, zeroing in on the exchange of the orbital angular momenta between the optical vortices and the magnetic quasi-vortices. We find that the conservation of the orbital angular momentum results in different nonreciprocal behaviors in the Brillouin light scattering. New avenues for chiral optics and opto-spintronics can be opened up by taking the orbital angular momenta as a new degree of freedom for cavity optomagnonics., Comment: 5 pages, 4 figures (1 supplemental figure)

Photon detectors are an elementary tool to measure electromagnetic waves at the quantum limit and are heavily demanded in the emerging quantum technologies such as communication, sensing, and computing. Of particular interest is a quantum non-demolition (QND) type detector, which projects the quantum state of a photonic mode onto the photon-number basis without affecting the temporal or spatial properties. This is in stark contrast to conventional photon detectors which absorb a photon to trigger a `click' and thus inevitably destroy the photon. The long-sought QND detection of a flying photon was recently demonstrated in the optical domain using a single atom in a cavity. However, the counterpart for microwaves has been elusive despite the recent progress in microwave quantum optics using superconducting circuits. Here, we implement a deterministic entangling gate between a superconducting qubit and a propagating microwave pulse mode reflected by a cavity containing the qubit. Using the entanglement and the high-fidelity qubit readout, we demonstrate a QND detection of a single photon with the quantum efficiency of 0.84, the photon survival probability of 0.87, and the dark-count probability of 0.0147. Our scheme can be a building block for quantum networks connecting distant qubit modules as well as a microwave photon counting device for multiple-photon signals., Comment: 16 pages, 12 figures, 1 table