Search for neutrinos from annihilation of captured low-mass dark matter particles in the Sun by Super-Kamiokande
Kamiokande Collaboration, K. Choi, K. Abe, Y. Haga, Y. Hayato, K. Iyogi, J. Kameda, Y. Kishimoto, M. Miura, S. Moriyama, M. Nakahata, Y. Nakano, S. Nakayama, H.… 展开作者
Kamiokande Collaboration, K. Choi, K. Abe, Y. Haga, Y. Hayato, K. Iyogi, J. Kameda, Y. Kishimoto, M. Miura, S. Moriyama, M. Nakahata, Y. Nakano, S. Nakayama, H. Sekiya, M. Shiozawa, Y. Suzuki, A. Takeda, T. Tomura, R. A. Wendell, T. Irvine, 2 T. Kajita, I. Kametani, 2 K. Kaneyuki, K. P. Lee, Y. Nishimura, 2 K. Okumura, T. McLachlan, 2 L. Labarga, E. Kearns, J. L. Raaf, 4 J. L. Stone, L. R. Sulak, 4 S. Berkman, 5 H. A. Tanaka, 5 S. Tobayama, M. Goldhaber, G. Carminati, W. R. Kropp, S. Mine, A. Renshaw, M. B. Smy, H. W. Sobel, K. S. Ganezer, J. Hill, N. Hong, J. Y. Kim, I. T. Lim, T. Akiri, A. Himmel, K. Scholberg, C. W. Walter, T. Wongjirad, T. Ishizuka, S. Tasaka, J. S. Jang, J. G. Learned, S. Matsuno, S. N. Smith, T. Hasegawa, T. Ishida, T. Ishii, T. Kobayashi, T. Nakadaira, K. Nakamura, Y. Oyama, K. Sakashita, T. Sekiguchi, T. Tsukamoto, A. T. Suzuki, Y. Takeuchi, C. Bronner, S. Hirota, K. Huang, K. Ieki, M. Ikeda, T. Kikawa, A. Minamino, T. Nakaya, K. Suzuki, S. Takahashi, Y. Fukuda, Y. Itow, G. Mitsuka, P. Mijakowski, J. Hignight, J. Imber, C. K. Jung, C. Yanagisawa, H. Ishino, A. Kibayashi, Y. Koshio, T. Mori, M. Sakuda, T. Yano, Y. Kuno, R. Tacik, S. B. Kim, H. Okazawa, Y. Choi, K. Nishijima, M. Koshiba, Y. Totsuka, M. Yokoyama, K. Martens, Ll. Marti, M. R. Vagins, J. F. Martin, P. de Perio, A. Konaka, M. J. Wilking, S. Chen, Y. Zhang, R. J. Wilkes
Super-Kamiokande (SK) can search for weakly interacting massive particles (WIMPs) by detecting neutrinos produced from WIMP annihilations occurring inside the Sun. In this analysis, we include neutrino events with interaction vertices in the detector in addition to upward-going muons produced in the surrounding rock. Compared to the previous result, which used the upward-going muons only, the signal acceptances for light (few-GeV/$c^2$ $\sim$ 200-GeV/$c^2$) WIMPs are significantly increased. We fit 3903 days of SK data to search for the contribution of neutrinos from WIMP annihilation in the Sun. We found no significant excess over expected atmospheric-neutrino background and the result is interpreted in terms of upper limits on WIMP-nucleon elastic scattering cross sections under different assumptions about the annihilation channel. We set the current best limits on the spin-dependent (SD) WIMP-proton cross section for WIMP masses below 200 GeV/$c^2$ (at 10 GeV/$c^2$, 1.49$\times 10^{-39}$ cm$^2$ for $χχ\rightarrow b \bar{b}$ and 1.31$\times 10^{-40}$ cm$^2$ for $χχ\rightarrowτ^+τ^-$ annihilation channels), also ruling out some fraction of WIMP candidates with spin-independent (SI) coupling in the few-GeV/$c^2$ mass range.
This work presents indirect searches for dark matter (DM) as WIMPs (Weakly Interacting Massive Particles) using neutrino data recorded by the Super-Kamiokande detector from 1996 to 2014. The results of the search for WIMP-induced neutrinos from the Sun and the Milky Way are discussed. We looked for an excess of neutrinos from the Sun/Milky Way direction compared to the expected atmospheric neutrino background. Event samples including both electron and muon neutrinos covering a wide range of neutrino energies (GeV to TeV) were used, with sensitivity to WIMP masses down to tens of GeV. Various W…
We point out that two models that reconcile the neutron lifetime anomaly via dark decays of the neutron, also predict dark matter-neutron ($\barχ-n$) annihilation that may be observable in neutron-antineutron oscillation and proton decay searches at Super-Kamiokande, Hyper-Kamiokande and DUNE. We study signatures of $\barχn\to γπ^0$ (or multi-$π^0$) and $\barχn\to ϕγπ^0$ (or $ϕ+$multi-$π^0$), where $ϕ$ is an almost massless boson in one of the two models.
Indirect detection of dark matter via its annihilation products is a key technique in the search for dark matter in the form of weakly interacting massive particles (WIMPs). Strong constraints exist on the annihilation of WIMPs to highly visible Standard Model final states such as photons or charged particles. In the case of s-wave annihilation, this typically eliminates thermal relic cross sections for dark matter of mass below $\cal{O}$(10) GeV. However, such limits typically neglect the possibility that dark matter may annihilate to assumed invisible or hard-to-detect final states, such as …
Recent results from a 282 kiloton-year exposure of the Super-Kamiokande detector to atmospheric neutrinos are presented. The data when fit both by themselves and in conjunction with constraints from the T2K and reactor neutrino experiments show a weak, though insignificant, preference for the normal mass hierarchy at the level of ~1 sigma. Searches for evidence of oscillations into a sterile neutrino have resulted in limits on the parameters governing their mixing, |U_mu4}|^2 <0.041 and |U_tau4|^2 < 0.18 at 90% C.L. A similar search for an indication of Lorentz-invariance violating oscillation…
A potential source of high energy neutrinos is the annihilation of Weakly Interacting Massive Particles (WIMPs) collecting in gravitational potential wells such as the centers of the Earth, the Sun, or the Galaxy. A search for such a WIMP annihilation signal using the Super-Kamiokande (Super-K) detector is presented. Super-K observes 1.1 upward through-going muons per day. These events are caused by high energy (typical E_nu ~ 100 GeV) nu_mu interactions in the rock under the detector, and are generally consistent with the expected flux from atmospheric neutrinos. No enhancement of the neutrin…
We examine models and prospects for proton annihilation to dileptons, a process which violates baryon and lepton number each by two. We determine that currently Super-Kamiokande would place the most draconian bound on $pp \rightarrow \ell^+ \ell^+$, ruling out new physics below a scale of $\sim 1.6$ TeV. We also find present and future hadron collider sensitivity to these processes. While 8 TeV LHC data excludes new physics at a scale below $\sim 800$ GeV, the reach of a 14 TeV LHC run is $\sim 1.8$ TeV, putting it on par with the sensitivity of Super-Kamiokande. On the other hand, a 100 TeV p…
We study the ability of the Hyper-Kamiokande (HyperK) experiment, currently under construction, to constrain a neutrino signal produced via the annihilation of dark matter captured in the Sun. We simulate upward stopping and upward through-going muon events at HyperK, using Super-Kamiokande (SuperK) atmospheric neutrino results for validation, together with fully and partially contained events. Considering the annihilation of dark matter to various standard model final states, we determined the HyperK sensitivity to the dark matter spin-dependent scattering cross-section. We find that HyperK w…
We consider the prospects for testing the dark matter interpretation of the DAMA/LIBRA signal with the Super-Kamiokande experiment. The DAMA/LIBRA signal favors dark matter with low mass and high scattering cross section. We show that these characteristics imply that the scattering cross section that enters the DAMA/LIBRA event rate determines the annihilation rate probed by Super-Kamiokande. Current limits from Super-Kamiokande through-going events do not test the DAMA/LIBRA favored region. We show, however, that upcoming analyses including fully-contained events with sensitivity to dark matt…
Dark matter can be boosted by various mechanisms, which may produce characteristic signals that are different from those of canonical dark matter. We show that the semi-annihilation $χχ\to\barχν$ produces signals that are distinctive from those of other semi-annihilation and standard dark matter annihilation processes. Because the boosted dark matter produced by the semi-annihilation process is regarded as a high-energy neutrino, the total flux of the dark matter and the accompanying neutrino produce double peaks in the energy close to the dark matter mass. We show that it will be possible to …
A subset of neutrino-induced upward through-going muons in the Super-Kamiokande detector consists of high energy muons which lose energy through radiative processes such as bremsstrahlung, e^{+} e^{-} pair production and photonuclear interactions. These ``upward showering muons'' comprise an event sample whose mean parent neutrino energy is approximately 1 TeV. We show that the zenith angle distribution of upward showering muons is consistent with negligible distortion due to neutrino oscillations, as expected of such a high-energy neutrino sample. We present astronomical searches using these …
The recent results of the EDGES collaboration indicate that during the era of reionization, the primordial gas was much colder than expected. The cooling of the gas could be explained by interactions between dark matter (DM) and particles in the primordial gas. Constraints from cosmology and particle experiments indicate that this DM should be light ($\sim$10-80 MeV), carry a small charge ($ε\sim 10^{-6}$-$10^{-4}$), and only make up a small fraction of the total amount of DM. Several constraints on the DM parameter space have already been made. We explore the yet unconstrained region in the c…
Technische Universität Dortmund（多特蒙德工业大学）；Universitat de València-CSIC（瓦伦西亚大学-西班牙国家研究委员会）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学）；Kavli Institute for the Physics and Mathematics of the Universe (WPI)（卡弗里宇宙物理起源研究所）
The largest underground neutrino observatory, Super-Kamiokande, located near Kamioka, Japan has been collecting data since April 1996. It is located at a depth of roughly 2.7 kmwe in a zinc mine under a mountain, and has an effective area for detecting entering-stopping and through-going muons of about $1238 m^2$ for muons of $>1.7 GeV$. These events are collected at a rate of 1.5 per day from the lower hemisphere of arrival directions, with 2.5 muons per second in the downgoing direction. We report preliminary results from 229 live days analyzed so far with respect to zenith angle variation o…
We present the result of an indirect search for high energy neutrinos from WIMP annihilation in the Sun using upward-going muon (upmu) events at Super-Kamiokande. Datasets from SKI-SKIII (3109.6 days) were used for the analysis. We looked for an excess of neutrino signal from the Sun as compared with the expected atmospheric neutrino background in three upmu categories: stopping, non-showering, and showering. No significant excess was observed. The 90% C.L. upper limits of upward-going muon flux induced by WIMPs of 100 GeV/c$^2$ were 6.4$\times10^{-15}$ cm$^{-2}$ sec$^{-1}$ and 4.0$\times10^{-…
The observation of GeV neutrinos coming from the Sun would be an unmistakable signal of dark matter. Current neutrino detectors have so far failed to detect such a signal, however, and bounds from direct and indirect dark matter searches may significantly restrict the possibility of observing it in future experiments such as Hyper-Kamiokande or IceCube-Gen2. In this work, we assess in the light of current data and of expected experimental sensitivities, the prospects for the detection of a neutrino signal from dark matter annihilations in the Sun. To be as general as possible, equilibrium betw…
A search for boosted dark matter using 161.9 kiloton-years of Super-Kamiokande IV data is presented. We search for an excess of elastically scattered electrons above the atmospheric neutrino background, with a visible energy between 100 MeV and 1 TeV, pointing back to the Galactic Center or the Sun. No such excess is observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic Center and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced from cold dark matter annihilation or decay.
The dark sector may contain a dark photon that kinetically mixes with the Standard Model photon, allowing dark matter to interact weakly with normal matter. In previous work we analyzed the implications of this scenario for dark matter capture by the Sun. Dark matter will gather in the core of the Sun and annihilate to dark photons. These dark photons travel outwards from the center of the Sun and may decay to produce positrons that can be detected by the Alpha Magnetic Spectrometer (AMS-02) on the ISS. We found that the dark photon parameter space accessible to this analysis is largely constr…
The Hyper-Kamiokande (HyperK) experiment is expected to precisely measure the Diffuse Supernova Neutrino Background (DSNB). This requires that the backgrounds in the relevant energy range are well understood. One possible background that has not been considered thus far is the annihilation of low-mass dark matter (DM) to neutrinos. We conduct simulations of the DSNB signal and backgrounds in HyperK, and quantify the extent to which DM annihilation products can pollute the DSNB signal. We find that the presence of DM could affect the determination of the correct values of parameters of interest…
We explore detection prospects of a non-standard dark sector in the context of boosted dark matter. We focus on a scenario with two dark matter particles of a large mass difference, where the heavier candidate is secluded and interacts with the standard model particles only at loops, escaping existing direct and indirect detection bounds. Yet its pair annihilation in the galactic center or in the Sun may produce boosted stable particles, which could be detected as visible Cherenkov light in large volume neutrino detectors. In such models with multiple candidates, self-interaction of dark matte…
We investigate the prospects for distinguishing dark matter annihilation channels using the neutrino flux from gravitationally captured dark matter particles annihilating inside the sun. We show that, even with experimental error in energy reconstruction taken into account, the spectrum of contained muon tracks may be used to discriminate neutrino final states from the gauge boson/charged lepton final states and to determine their corresponding branching ratios. We also discuss the effect of $ν_τ$ regeneration inside the sun as a novel method to distinguish the flavor of final state neutrinos.…
We study novel scenarios where thermal dark matter (DM) can be efficiently captured in the Sun and annihilate into boosted dark matter. In models with semi-annihilating DM, where DM has a non-minimal stabilization symmetry, or in models with a multi-component DM sector, annihilations of DM can give rise to stable dark sector particles with moderate Lorentz boosts. We investigate both of these possibilities, presenting concrete models as proofs of concept. Both scenarios can yield viable thermal relic DM with masses O(1)-O(100) GeV. Taking advantage of the energetic proton recoils that arise wh…
We calculate the annihilation rate of weakly interacting massive particles (WIMPs) in the Sun as a function of their mass and elastic scattering cross section. One byproduct of the annihilation, muon neutrinos, may be observed by the next generation of neutrino telescopes. Previous estimates of the annihilation rate assumed that any WIMPs from the Galactic dark halo that are captured in the Sun by elastic scattering off solar nuclei quickly reach thermal equilibrium in the Sun. We show that the optical depth of the Sun to WIMPs and the gravitational forces from planets both serve to decrease t…
We present the results of indirect searches for Weakly Interacting Massive Particles (WIMPs) with 1679.6 live days of data from the Super-Kamiokande detector using neutrino-induced upward through-going muons. The search is performed by looking for an excess of high energy muon neutrinos from WIMP annihilations in the Sun, the core of the Earth, and the Galactic Center, as compared to the number expected from the atmospheric neutrino background. No statistically significant excess was seen. We calculate flux limits in various angular cones around each of the above celestial objects. We obtain c…
If dark matter self-annihilates into neutrinos or a second component of ("boosted") dark matter that is nucleophilic, the annihilation products may be detected with high rates via coherent nuclear scattering. A future multi-ten-tonne liquid xenon detector such as DARWIN, and a multi-hundred-tonne liquid argon detector, ARGO, would be sensitive to the flux of these particles in complementary ranges of $10-1000$ MeV dark matter masses. We derive these sensitivities after accounting for atmospheric and diffuse supernova neutrino backgrounds, and realistic nuclear recoil acceptances. We find that …
GUT monopoles captured by the Sun's gravitation are expected to catalyze proton decays via the Callan-Rubakov process. In this scenario, protons, which initially decay into pions, will ultimately produce ν_{e}, ν_μ and \barν_μ. After undergoing neutrino oscillation, all neutrino species appear when they arrive at the Earth, and can be detected by a 50,000 metric ton water Cherenkov detector, Super-Kamiokande (SK). A search for low energy neutrinos in the electron total energy range from 19 to 55 MeV was carried out with SK and gives a monopole flux limit of F_M(σ_0/1 mb) < 6.3 \times 10^{-24} …
We present a search for an excess of neutrino interactions due to dark matter in the form of Weakly Interacting Massive Particles (WIMPs) annihilating in the galactic center or halo based on the data set of Super-Kamiokande-I, -II, -III and -IV taken from 1996 to 2016. We model the neutrino flux, energy, and flavor distributions assuming WIMP self-annihilation is dominant to $ν\overlineν$, $μ^+μ^-$, $b\overline{b}$, or $W^+W^-$. The excess is in comparison to atmospheric neutrino interactions which are modeled in detail and fit to data. Limits on the self-annihilation cross section $\langle σ_…
If dark matter is efficiently captured by a planet, energy released in its annihilation can exceed that planet's total heat output. Building on prior work, we treat Earth's composition and dark matter capture in detail and present improved limits on dark matter-nucleon scattering cross sections for dark matter masses ranging from 0.1 to $10^{10}$ GeV. We also extend Earth limits by applying the same treatment to Mars. The scope of dark matter models considered is expanded to include spin-dependent nuclear interactions including isospin-independent, proton only, and neutron only interactions. W…
In this last paper in a series of three on weakly interacting massive particle (WIMP) dark matter in the solar system, we focus on WIMPs bound to the system by gravitationally scattering off of planets. We present simulations of WIMP orbits in a toy solar system consisting of only the Sun and Jupiter. As previous work suggested, we find that the density of gravitationally captured WIMPs at the Earth is small and largely insensitive to the details of elastic scattering in the Sun. However, we find that the density of gravitationally captured WIMPs may be affected by external Galactic gravitatio…
If dark matter has a sizable scattering cross section with nucleons, it can efficiently be captured by a neutron star. Its energy is then transferred to the neutron star as heat through the scattering and annihilation inside the star. This heating effect may be detectable via dedicated temperature observations of nearby old pulsars, providing an alternative method for dark matter searches. In this paper, we show that for electroweak multiplet dark matter this search strategy can probe the parameter region which is out of reach of future dark matter direct detection experiments. To see this sys…
If neutrino oscillation plays a role in explaining the atmospheric neutrino deficit, then the same phenomenon would necessarily affect also the dark matter indirect-detection signal which consists in a muon-neutrino flux produced by neutralino annihilation in the Earth core. In this paper we investigate to which extent the upgoing-muon signal originated by neutralinos captured inside the Earth would be affected by the presence of nu_mu -> nu_tau oscillation.
Dark matter (DM) scattering and its subsequent capture in the Sun can boost the local relic density, leading to an enhanced neutrino flux from DM annihilations that is in principle detectable at neutrino telescopes. We calculate the event rates expected for a radiative seesaw model containing both scalar triplet and singlet-doublet fermion DM candidates. In the case of scalar DM, the absence of a spin dependent scattering on nuclei results in a low capture rate in the Sun, which is reflected in an event rate of less than one per year in the current IceCube configuration with 86 strings. For si…
Radiative seesaw models have the attractive property of providing dark matter candidates in addition to the generation of neutrino masses. Here we present a study of neutrino signals from the annihilation of dark matter particles that have been gravitationally captured in the Sun in the framework of the scotogenic model. We compute expected event rates in the IceCube detector in its 86-string configuration. As fermionic dark matter does not scatter off nucleons due to its singlet nature and therefore does not accumulate in the Sun, we study the case of scalar dark matter with a scan over the p…
First observation of electron antineutrinos from nuclear reactors at Super-Kamiokande
Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo（神冈观测站，宇宙线研究所，东京大学）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, University of Tokyo（汤川理论物理与宇宙学研究所（WPI），东京大学高等研究院，东京大学）
After scattering off nuclei in the Sun, dark matter particles can be gravitationally captured by the Sun, accumulate in the Sun's core and annihilate into Standard Model particles. Neutrinos originating from these annihilations can be detected by the IceCube Neutrino Observatory, located at the South Pole. Due to the non-observation of these neutrinos, constraints on the standard spin-dependent and spin-independent dark matter-nucleon scattering cross sections have been placed. Based on these constraints, we present upper limits on the coupling constants of the non-relativistic effective theor…
Dark matter can be captured by celestial objects and accumulate at their centers, forming a core of dark matter that can collapse to a small black hole, provided that the annihilation rate is small or zero. If the nascent black hole is big enough, it will grow to consume the star or planet. We calculate the rate of dark matter accumulation in the Sun and Earth, and use their continued existence to place novel constraints on high mass asymmetric dark matter interactions. We also identify and detail less destructive signatures: a newly-formed black hole can be small enough to evaporate via Hawki…
We use the recent results on dark matter searches of the 22-string IceCube detector to probe the remaining allowed window for strongly interacting dark matter in the mass range 10^4<m_X<10^15 GeV. We calculate the expected signal in the 22-string IceCube detector from the annihilation ofsuch particles captured in the Sun and compare it to the detected background. As a result, the remaining allowed region in the mass versus cross sectionparameter space is ruled out. We also show the expected sensitivity of the complete IceCube detector with 86 strings.
