We propose a novel framework where light (sub-GeV) dark matter (DM) is detectable with future MeV gamma-ray telescopes without conflicting with Cosmic Microwave Background (CMB) data. The stable DM particle $χ$ has a very low thermal relic abundance due to its large pair-annihilation cross section. The DM number density is stored in a heavier, meta-stable partner $ψ$ with suppressed pair-annihilation rates, that does not perturb the CMB, and whose late-time decays $ψ\rightarrow χ$ fill the universe with $χ$ DM particles. We provide explicit, model-independent realizations for this framework, and discuss constraints on late-time decays, and thus on parameters of this setup, from CMB, Big Bang Nucleosynthesis, and Large Scale Structure.
String scenarios typically not only predict axion-like particles (ALPs) but also significant amounts of ALP dark radiation originating from the decay of the inflaton or a more general modulus. In this paper, we study the decay of such non-thermally produced relativistic (but massive) ALPs to photons. If the ALPs are sufficiently highly energetic, contribute to $ΔN_{\rm eff} \gtrsim {\cal O}(0.001)$ and have a mass $m_a\gtrsim$ MeV we find that, using observations of X-, and $γ$-rays, the CMB and BBN, very small values of the ALP-photon coupling can be probed, corresponding to an origin of this…
We consider a dark sector with $SU(3)_C \times U(1)_Y \times U(1)_X$ and three families of dark fermions that are chiral under dark $U(1)_X$ gauge symmetry, whereas scalar dark matter $X$ is the SM singlet. $U(1)_X$ dark symmetry is spontaneously broken by nonzero VEV of dark Higgs field $\langle Φ\rangle$, generating the masses of dark fermions and dark photon $Z^\prime$. The resulting dark Higgs boson $ϕ$ can be produced at the LHC by dark quark loop (involving 3 generation) and will decay into a pair of photon through charged dark fermion loop. Its decay width can be easily $\sim 45$ GeV du…
In addition to gravity, there might be another very weak interaction between the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark photons) mixing with our photons. If such A's exist, they could be searched for in a light-shining-through-a-wall experiment with a high energy electron beam. The electron energy absorption in a calorimeter (CAL1) is accompanied by the emission of bremsstrahlung A's in the reaction eZ -> eZA' of electrons scattering on nuclei due to the γ- A' mixing. A part of the primary beam energy is deposited in the CAL1, while the rest of the energy is transm…
We show that magnetic fields have the potential to significantly enhance a recently proposed light-shining-through-walls scenario in quantum-field theories with photons coupling to minicharged particles. Suggesting a dedicated laboratory experiment, we demonstrate that this particular tunneling scenario could provide access to a parameter regime competitive with the currently best direct laboratory limits on minicharged fermions below the $\mathrm{meV}$ regime. With present day technology, such an experiment has the potential to even overcome the best model-independent cosmological bounds on m…
We point out that a non-relativistic $\sim 2 $ GeV dark matter (DM) which interacts with visible matter through higher dimensional Rayleigh operators could explain the excess of "electron recoil" events recently observed by the Xenon1T collaboration. A DM scattering event results in a few keV photon that on average carries most of the deposited energy, while the nuclear recoil energy is only a subleading correction. Since the Xenon1T detector does not discriminate between electrons and photons, such events would be interpreted as excess of the keV electrons. Indirect constraints from dark matt…
It is shown that the Sun can become partially transparent to high energy photons in the presence of a pseudo-scalar. In particular, if the axion interpretation of the PVLAS result were true then up to 2% of GeV energy gamma rays might pass through the Sun, while an even stronger effect is expected for some axion parameters. We discuss the possibilities of observing this effect. Present data are limited to the observation of the solar occultation of 3C 279 by EGRET in 1991; 98% C.L. detection of a non-zero flux of gamma rays passing through the Sun is not yet conclusive. Since the same occultat…
Currently, there are a number of light-shining-through-walls experiments searching for hidden photons -- light, sub-eV-scale, abelian gauge bosons beyond the standard model which mix kinetically with the standard photon. We show that in the case that one of these experiments finds evidence for hidden photons, laser communications through matter, using methods from free-space optics, can be realized in the very near future, with a channel capacity of more than 1 bit per second, for a distance up to the Earth's diamater.
If the mysterious Fermi-LAT GeV gamma-ray excess is due to an unresolved population of millisecond pulsars (MSP) in the Galactic bulge, one expects this very same population to shine in X rays. For the first time, we address the question of what is the sensitivity of current X-ray telescopes to an MSP population in the Galactic bulge. To this end, we create a synthetic population of Galactic MSPs, building on an empirical connection between gamma- and X-ray MSP emission based on observed source properties. We compare our model with compact sources in the latest Chandra source catalog, applying…
Jožef Stefan Institute（约泽夫·斯特凡研究所）；Faculty of Mathematics and Physics, University of Ljubljana（卢布尔雅那大学数学物理学院）；Instituto de Física Corpuscular, Universitat de Valéncia – Consejo Superior de Investigaciones Científicas（瓦伦西亚大学-西班牙国家科研理事会粒子物理研究所）
We present a novel interpretation of the $γ$-ray diffuse emission measured by Fermi-LAT and H.E.S.S. in the Galactic center (GC) region and the Galactic ridge (GR). In the first part we perform a data-driven analysis based on PASS8 Fermi-LAT data: we extend down to few GeV the spectra measured by H.E.S.S. and infer the primary cosmic-ray (CR) radial distribution between 0.1 and 3 TeV. In the second part we adopt a CR transport model based on a position-dependent diffusion coefficient. Such behavior reproduces the radial dependence of the CR spectral index recently inferred from the Fermi-LAT o…
In a broad class of consistent models, MeV to few-GeV dark matter interacts with ordinary matter through weakly coupled GeV-scale mediators. We show that a suitable meter-scale (or smaller) detector situated downstream of an electron beam-dump can sensitively probe dark matter interacting via sub-GeV mediators, while B-factory searches cover the 1-5 GeV range. Combined, such experiments explore a well-motivated and otherwise inaccessible region of dark matter parameter space with sensitivity several orders of magnitude beyond existing direct detection constraints. These experiments would also …
Besides general features of two-boson mass distributions, experimental results are are discussed. Furthermore, E(38 MeV) and Z(57.5 GeV) are highlighted.
Light Dark Matter (DM), defined here as having a mass between 1 MeV and about 1 GeV, is an interesting possibility both theoretically and phenomenologically, at one of the frontiers of current progress in the field of DM searches. Its indirect detection via gamma-rays is challenged by the scarcity of experiments in the MeV-GeV region. We look therefore at lower-energy X-ray data from the Integral telescope, and compare them with the predicted DM flux. We derive bounds which are competitive with existing ones from other techniques. Crucially, we include the contribution from inverse Compton sca…
Both cosmology and astrophysics suggest the possible existence of sterile neutrino which is a dark matter candidate. The interaction of sterile neutrinos with matter in keV energy scale has been studied in the literature. In this paper we study the interaction of sterile neutrinos with atoms and their role on ionization of atoms in MeV and GeV energy scale. We also study the interaction of sterile neutrinos with nuclei in the MeV and GeV energy scale. We obtain the relevant cross sections for both these two interactions. Finally we compare our results with the results of keV energy range.
GeV-scale dark matter is an increasingly attractive target for direct detection, indirect detection, and collider searches. Especially for masses in the MeV to GeV range, indirect detection is expected to give a leading constraint. In that range, dark matter annihilations into hadronic final states produce a challenging zoo of light hadronic resonances. With an update of Herwig7, we provide a modeling of these processes and study energy spectra from annihilation through a vector mediator. We cover dark matter masses between 250 MeV and 5 GeV and include an error estimate. This opens up new opp…
The decay constants of pseudoscalar mesons are calculated in a relativistic quark model which assumes that mesons are made of a valence quark antiquark pair and of an effective vacuum like component. The results are given in terms of quark masses and of some free parameters entering the expression of the internal wave functions of the mesons. By using the pion and kaon decay constants $F_{π^+}=130.7~MeV,~F_{K^+}=159.8~MeV$ to fix the parameters of the model one gets $60~MeV\leq F_{D^+}\leq 185~MeV,~95~MeV\leq F_{D_s}\leq230~MeV,~80~MeV\leq F_{B^+}\leq205~MeV$ for the light quark masses $m_u=5.…
The masses of excited charmed mesons are shown to decrease by $\sim (50-150)$~MeV due to a flattening of the confining potential at large distances, which effectively takes into account open decay channels. The scale of the mass shifts is similar to that in charmonium for $ψ(4660)$ and $χ_{c0}(4700)$. The following masses of the first excitations: $M(2\,{}^3P_0)=2874$~MeV, $M(2\,{}^3P_2)=2968$~MeV, $M(2\,{}^3D_1)=3175$~MeV, and $M(2\,{}^3D_3)=3187$~MeV, and second excitations: $M(3\,{}^1S_0)=3008$~MeV, $M(3\,{}^3S_1)=3062$~MeV, $M(3\,{}^3P_0)=3229$~MeV, and $M(3\,{}^3P_2) =3264$~MeV, are predi…
The first direct detection limits on dark matter in the MeV to GeV mass range are presented, using XENON10 data. Such light dark matter can scatter with electrons, causing ionization of atoms in a detector target material and leading to single- or few-electron events. We use 15 kg-days of data acquired in 2006 to set limits on the dark-matter-electron scattering cross section. The strongest bound is obtained at 100 MeV where sigma_e < 3 x 10^{-38} cm^2 at 90% CL, while dark matter masses between 20 MeV and 1 GeV are bounded by sigma_e < 10^{-37} cm^2 at 90% CL. This analysis provides a first p…
Axion-like particles (ALPs), relatively light (pseudo-)scalars coupled to two gauge bosons, are a common feature of many extensions of the Standard Model. Up to now there has been a gap in the sensitivity to such particles in the MeV to 10 GeV range. In this note we show that LEP data on $Z\toγγ$ decays provides significant constraints in this range (and indeed up to the $Z$-mass). We also discuss the sensitivities of LHC and future colliders. Particularly the LHC shows promising sensitivity in searching for a pseudo-scalar with $4 \lesssim m_a \lesssim 60$ GeV in the channel $pp \to 3 γ$ with…
Improved upper bounds are presented on the coupling $|U_{e4}|^2$ of an electron to a sterile neutrino $ν_4$ from analyses of data on nuclear and particle decays, including superallowed nuclear beta decays, the ratios $R^{(π)}_{e/μ}=BR(π^+ \to e^+ ν_e)/BR(π^+ \to μ^+ ν_μ)$, $R^{(K)}_{e/μ}$, $R^{(D_s)}_{e/τ}$, and $B^+_{e 2}$ decay, covering the mass range from MeV to GeV.
The strong OZI allowed decays of the first radial excited states $B(2S)$ and $D(2S)$ are studied in the instantaneous Bethe-Salpeter method, and by using these OZI allowed channels we estimate the full decay widths: $Γ_{B^0(2S)}=24.4$ MeV, $Γ_{B^+(2S)}=23.7$ MeV, $Γ_{D^0(2S)}=11.3$ MeV and $Γ_{D^+(2S)}=11.9$ MeV. We also predict the masses of them: $M_{B^0(2S)}=5.777$ GeV, $M_{B^+(2S)}=5.774$ GeV, $M_{D^0(2S)}=2.390$ GeV and $M_{D^+(2S)}=2.393$ GeV.
Recently, the BESIII Collaboration reported three resonances: $X(2232)$ with $M = 2232 \pm 19 \pm 27$ MeV and $Γ= 93 \pm 53 \pm 20$ MeV, $X(2200)$ whose mass $M = 2200 \pm 11 \pm 17$ MeV and width $Γ= 74 \pm 20 \pm 24$ MeV as well as $X(2222)$ which has mass of $2222 \pm 7 \pm 2$ MeV and the width of $59 \pm 30 \pm 6$ MeV. The mass spectrum of $ω$ meson family is studied utilizing the modified Godfrey-Isgur model, and the two-body strong decays of $X(2232)$, $X(2200)$ and $X(2222)$ within two different approaches of the $^3P_0$ model. We find that the newly discovered states $X(2232)$, $X(2200…
We have performed a new model independent amplitude analysis of reaction $π^- p \to π^- π^+ n$ measured at CERN at 17.2 GeV/c on polarized target. The analysis extends the range of dipion mass from 600--880 MeV used in the previous study to 580--1080 MeV. Our purpose is to study the role of $f_0(980)$ interference and to better determine the resonance parameters of $σ(750)$ resonance from fits to both S-wave amplitudes $|\bar S|^2Σ$ and $|S|^2Σ$ with recoil nucleon transversities ``up'' and ``down'', respectively. This work is the first attempt to determine resonance parameters of a resonance …
In this article, we study the $Λ_c$ and $Λ_b$ baryons in the nuclear matter using the QCD sum rules, and obtain the in-medium masses $M_{Λ_c}^*=2.335\,\rm{GeV}$, $M_{Λ_b}^*=5.678\,\rm{GeV}$, the in-medium vector self-energies $Σ^{Λ_c}_v=34\,\rm{MeV}$, $Σ^{Λ_b}_v=32\,\rm{MeV}$, and the in-medium pole residues $λ_{Λ_c}^*=0.021\,\rm{GeV}^3$, $λ_{Λ_b}^*=0.026\,\rm{GeV}^3$. The mass-shifts are $M_{Λ_c}^*-M_{Λ_c}=51\,\rm{MeV}$ and $M_{Λ_b}^*-M_{Λ_b}=60\,\rm{MeV}$, respectively.
We propose a variation, based on very low energy and extremely intense photon sources, on the well established technique of Light-Shining-through-Wall (LSW) experiments for axion-like particle searches. With radiation sources at 30 GHz, we compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude, for masses m_a <~ 0.01~meV. This could motivate research and development programs on dedicated single-photon sub-THz detectors.
I discuss old and new determinations of the light quark masses using lattice QCD. Most lattice results using various approximations can be fit together in a simple picture which is consistent with lower values than conventionally supposed: in the quenched approximation for the strange quark mass in the MS bar scheme, m_s(2 GeV) = 95 (16) MeV, and for the average of the u and d quark masses, m_l(2 GeV) = 3.6 (6) MeV. An estimate of the effects of light quark loops yields answers lower still: m_s(2 GeV) in the range 54 - 92 MeV, and m_l(2 GeV) in the range 2.1 - 3.5 MeV.
Recent discovery of the afterglow emission from short gamma-ray bursts suggests that binary neutron star or black hole-neutron star binary mergers are the likely progenitors of these short bursts. The accretion of neutron star material and its subsequent ejection by the central engine implies a neutron-rich outflow. We consider here a neutron-rich relativistic jet model of short bursts, and investigate the high energy neutrino and photon emission as neutrons and protons decouple from each other. We find that upcoming neutrino telescopes are unlikley to detect the 50 GeV neutrinos expected in t…
Recent data from the NA49 experiment on directed and elliptic flow for Pb+Pb reactions at CERN-SPS are compared to calculations with a hadron-string transport model, the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. The rapidity and transverse momentum dependence of the directed and elliptic flow, i.e. $v_1$ and $v_2$, are investigated. The flow results are compared to data at three different centrality bins. Generally, a reasonable agreement between the data and the calculations is found. Furthermore, the energy excitation functions of $v_1$ and $v_2$ from $E_{\rm beam}=90A$ Me…
In this paper we investigate the phenomenology of a very light scalar, $h$, with mass 100 MeV $<m_h<$ 10 GeV, mixing with the SM Higgs. As a benchmark model we take the real singlet scalar extension of the SM. We point out apparently unresolved uncertainties in the branching ratios and lifetime of $h$ in a crucial region of parameter space for LHC phenomenology. Bounds from LEP, meson decays and fixed target experiments are reviewed. We also examine prospects at the LHC. For $m_h \lesssim m_B$ the dominant production mechanism is via meson decay; our main result is the calculation of the diffe…
Cornering MeV-GeV Axions and Dark Photons with LDMX
SLAC National Accelerator Laboratory（斯坦福直线加速器中心）；Department of Physics, Stanford University（斯坦福大学物理系）；Leinweber Institute for Theoretical Physics（莱因韦伯理论物理研究所）
We describe a novel search for MeV-to-GeV-mass dark matter, in which the dark matter scatters off electrons in a scintillating target. The excitation and subsequent de-excitation of the electron produces one or more photons, which could be detected with an array of cryogenic low-noise photodetectors, such as transition edge sensors (TES) or microwave kinetic inductance devices (MKID). Scintillators may have distinct advantages over other experiments searching for a low ionization signal from sub-GeV DM. First, the detection of one or a few photons may be technologically easier. Second, since n…
The spectra of heavy quarkonia are studied in two approaches: with the use of the Afonin-Pusenkov representation of the Regge trajectory for the squared excitation energy $E^2(nl)$ (ERT), and using the relativistic Hamiltonian with the universal interaction. The parameters of the ERTs are extracted from experimental mass differences and their values in bottomonium: the intercept $a(b\bar b)=0.131\,$GeV$^2$, the slope of the orbital ERT $b_l(b\bar b) =0.50$\,GeV$^2$, and the slope of the radial ERT, $b_n(b\bar b)=0.724$\,GeV$^2$, appear to be smaller than those in charmonium, where $a(c\bar c)=…
The Quasi-Elastic (QE) contribution of the nuclear inclusive electron model developed in Nucl. Phys. A627 543 (1997) is extended to the study of neutrino/antineutrino Charged Current (CC) and Neutral Current (NC) induced nuclear reactions at intermediate energies. Long range nuclear (RPA) correlations, Final State Interaction (FSI) and Coulomb corrections are included within the model. RPA correlations are shown to play a crucial role in the whole range (100--500 MeV) of studied neutrino energies. Results for inclusive muon capture for different nuclei through the Periodic Table are also discu…
In $R$-parity violating supersymmetry, the gravitino as the lightest supersymmetric particle (LSP) is a good candidate for dark matter, with the interesting characteristic to be detectable through $γ$-ray telescopes. We extend this analysis considering an axino next-to-LSP (NLSP) as a coexisting dark matter particle contributing with a detectable signal in the $γ$-ray spectrum. The analysis is carried out in the framework of the $μν$SSM, which solves the $μ$ problem reproducing simultaneously neutrino data only with the addition of right-handed neutrinos. We find that important regions of the …
A detailed discussion is given of the analysis of recent data to obtain improved upper bounds on the couplings $|U_{e4}|^2$ and $|U_{μ4}|^2$ for a mainly sterile neutrino mass eigenstate $ν_4$. Using the excellent agreement among ${\cal F}t$ values for superallowed nuclear beta decay, an improved upper limit is derived for emission of a $ν_4$. The agreement of the ratios of branching ratios $R^{(π)}_{e/μ}=BR(π^+ \to e^+ ν_e)/BR(π^+ \to μ^+ ν_μ)$, $R^{(K)}_{e/μ}$, $R^{(D_s)}_{e/τ}$, $R^{(D_s)}_{μ/τ}$, and $R^{(D)}_{e/τ}$, and the branching ratios $BR(B^+\rightarrow e^+ν_e)$ and $BR(B^+\rightarr…
We investigate the masses of the light quarks with lattice QCD. We show that most of the large dependence on the lattice spacing, a, observed in previous determinations using Wilson fermions is removed with the use of an O(a) corrected action. In the quenched approximation, we obtain for the strange quark MS bar mass m_s(2 GeV) = 95 (16) MeV, and for the average of the up and down quark masses m_l(2 GeV) = 3.6 (6) MeV. Short distance arguments and existing staggered fermion calculations make it likely that the answers including the effects of quark loops lie 20 % to 40 % below this: m_s(2 GeV)…
Magnetic fields may play a dominant role in gamma-ray bursts, and recent observations by the Fermi satellite indicate that GeV radiation, when detected, arrives delayed by seconds from the onset of the MeV component. Motivated by this, we discuss a magnetically dominated jet model where both magnetic dissipation and nuclear collisions are important. We show that, for parameters typical of the observed bursts, such a model involving a realistic jet structure can reproduce the general features of the MeV and a separate GeV radiation component, including the time delay between the two. The model …
We study the sensitivity of the NO$ν$A near detector to MeV-GeV dark matter while operating symbiotically with the neutrino program. We find that NO$ν$A could explore a large new region of parameter space over the next few years for dark matter masses below 100 MeV, reaching the thermal target for a scalar dark matter particle for some masses. This result represents a significant improvement over existing probes such as Babar, E137, and LSND.
We present results for the light meson masses and decay constants as obtained from calculations with the non-perturbatively improved (`Alpha') action and operators on a 24^3 \times 64 lattice at beta = 6.2, in the quenched approximation. The analysis was performed in a way consistent with O(a) improvement. We obtained: reasonable agreement with experiment for the hyperfine splitting; f_K=156(17) MeV, f_pi =139(22) MeV, f_K/f_pi = 1.13(4) ; f_{K*}=219(7) MeV, f_rho =199(15) MeV, f_phi =235(4) MeV; f_{K*}^{T}(2 GeV) = 178(10) MeV, f_rho^{T}(2 GeV) =165(11) MeV, where f_V^{T} is the coupling of t…
Results are presented on a partial wave analysis of the Omega Eta final state produced in Pi- Proton interactions at 18 GeVc where Omega -> Pi+ Pi- Pi0, Pi0 -> 2 Gammas, and Eta -> 2 Gammas. We observe the previously unreported decay mode Omega(1650) -> Omega Eta and a new 1(+-) meson state h1(1595) with a mass M=1594(15)(+10)(-60) MeV/c^2 and a width Gamma=384(60)(+70)(-100) MeV/c^2. The h1(1595) state exhibits resonant-like phase motion relative to the Omega(1650).
A gamma-ray burst fireball is likely to contain an admixture of neutrons, in addition to protons, in essentially all progenitor scenarios. Inelastic collisions between differentially streaming protons and neutrons in the fireball produce muon neutrinos (antineutrinos) of ~ 10 GeV as well as electron neutrinos (antineutrinos) of ~ 5 GeV, which could produce ~ 7 events/year in kilometer cube detectors, if the neutron abundance is comparable to that of protons. Photons of ~ 10 GeV from pi-zero decay and ~ 100 MeV electron antineutrinos from neutron decay are also produced, but will be difficult t…
We reconsider the determinations of the strange quark mass m_s from e+e- into hadrons data using a new combination of FESR and revisiting the existing tau-like sum rules by including non-resonant contributions to the spectral functions. To order alpha_s^3 and including the tachyonic gluon mass lambda^2 contribution, which phenomenologically parametrizes the UV renormalon effect into the PT series, we obtain the invariant mass m_s=(119 +- 17)MeV leading to: m_s(2 GeV)=(104+- 15)MeV. Combining this value with the recent and independent phenomenological determinations from some other channels, to…
We propose to search for millicharged particles in electron colliders operated with the center-of-mass energies at ${\cal O}$(1-10) GeV, which include Belle II, BESIII, BaBar, and also the proposed experiment STCF. We use the monophoton final state at electron colliders to probe the parameter space of millicharged particles, that is spanned by millicharge $ε$ and mass $m$. We find that electron colliders have sensitivity to the previously unexplored parameter space for millicharged particles with MeV-GeV mass: $ε\lesssim {\cal O}(10^{-1})$ for $0.5$ GeV $\lesssim m \lesssim 3.5$ GeV in BaBar, …
The recent ALEPH measurements of the inclusive Cabibbo--suppressed decay width of the $τ$ and several moments of its invariant mass distribution are used to determine the value of the strange quark mass. We obtain, in the $\bar{\rm MS}$ scheme, $m_s(M_τ^2) = (119\pm 24)$ MeV, which corresponds to $ m_s(1 {\rm GeV}^2) = (164 \pm 33) {\rm MeV}, m_s(4 {\rm GeV}^2) = (114\pm 23) {\rm MeV} $.
Two-photon and two-gluon annihilation rates of $η_c$, $η'_c$, $η_b$ and $η'_b$ are estimated in the relativistic Salpeter method. By solving the full Salpeter equation with a well defined relativistic wave function, we estimate $M_{η_c}=2.979\pm 0.432$ GeV, $M_{η'_c}=3.566\pm 0.437$ GeV, $M_{η_b}=9.364\pm 1.120$ GeV and $M_{η'_b}=9.941\pm 1.112$ GeV. We calculated the transition amplitude using the Mandelstam formalism and estimate the decay widths: $Γ(η_c \to 2γ)=7.14\pm 0.95$ KeV, $Γ(η'_c \to 2γ)=4.44\pm 0.48$ KeV, $Γ(η_b \to 2γ)=0.384\pm 0.047$ KeV and $Γ(η'_b \to 2γ)=0.191\pm 0.025$ KeV. W…
Next generation neutrino oscillation experiments will need a quantitative understanding of neutrino-nucleus interaction far better than ever. Kinematics covered by the relevant neutrino-nucleus interaction spans wide region, from the quasi-elastic, through the resonance region, to the deeply inelastic scattering region. The neutrino-nucleus interaction in each region has quite different characteristics. Obviously, it is essential to combine different expertise to construct a unified model that covers all the kinematical region of the neutrino-nucleus interaction. Recently, several experimental…
We study the sensitivity to sub-GeV dark sectors of high energy ($ \geq100$ GeV) proton fixed target experiments such as the Main Injector and the future Long-Baseline Neutrino Facility (LBNF). We focus on off-axis detectors since they have been shown to be the ideal location to reduce the neutrino background. We consider MiniBooNE as an off-axis detector for the NuMI facility and a hypotetical detector for LBNF located 200 m away from the target and 6.5 degrees off-axis. We find that with the existing data, MiniBoone can explore new regions of the parameter space for leptophobic dark forces i…
Axino and gravitino are promising candidates to solve the dark matter (DM) problem in the framework of supersymmetry. In this work, we assume that the axino is the lightest supersymmetric particle (LSP), and therefore contributes to DM. In the case of R-parity violating models, the axino can decay into a neutrino-photon pair with a lifetime much longer than the age of the Universe, yielding a potentially detectable signal. Interestingly, a gravitino next-to-LSP (NLSP) can live enough as to contribute to the relic density. We study both scenarios, only axino LSP as DM, and axino LSP with gravit…
Recent theoretical and experimental improvements in the determination of charm and bottom quark masses are discussed. The final results, $m_c(3 \text{GeV})=986(13) $MeV and $m_b(m_b)=4163(16) $MeV represent, together with a closely related lattice determination $m_c(3 {\rm GeV})=986(10) $MeV, the presently most precise determinations of these two fundamental Standard Model parameters. A critical analysis of the theoretical and experimental uncertainties is presented.
We survey the sensitivity of past and present neutrino experiments to MeV-GeV scale dark matter, and find that these experiments possess novel sensitivity that has not yet fully explored. NO$ν$A and BEBC are found to rule out the scalar thermal target for dark matter masses between 10 MeV to 100 MeV with existing data, while CHARM-II and MINER$ν$A place somewhat weaker limits. These limits can be dramatically improved by off-axis searches using the NuMI beamline and the MicroBooNE, MiniBooNE or ICARUS detectors, and can even begin to probe the Majorana thermal target. We conclude that past and…
