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Kangsoon Park

Bio: Kangsoon Park is an academic researcher from Seokyeong University. The author has contributed to research in topics: Dark matter & Scintillator. The author has an hindex of 17, co-authored 49 publications receiving 2749 citations.


Papers
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Journal ArticleDOI
TL;DR: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations.
Abstract: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six $2.8\text{ }\text{ }{\mathrm{GW}}_{\mathrm{th}}$ reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is $0.920\ifmmode\pm\else\textpm\fi{}0.009(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.014(\mathrm{syst})$. From this deficit, we determine ${sin }^{2}2{\ensuremath{\theta}}_{13}=0.113\ifmmode\pm\else\textpm\fi{}0.013(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.019(\mathrm{syst})$ based on a rate-only analysis.

1,979 citations

Journal ArticleDOI
TL;DR: New constraints on the dark matter-induced annual modulation signal are presented using 1.7 years of COSINE-100 data with a total exposure of 97 kg yr and best fit values for modulation amplitude and phase are observed.
Abstract: We present new constraints on the dark matter-induced annual modulation signal using 1.7\,years, of COSINE-100 data with a total exposure of 97.7\,kg⋅years. The COSINE-100 experiment, consisting of 106\,kg of NaI(Tl) target, is designed to carry out a model-independent test of DAMA/LIBRA's claim by searching for the same annual modulation signal using the same NaI(Tl) target. The crystal data show 2.7 counts/keV/kg/day background rate on average in the 2--6 keV energy region of interest. Using a chi-squared minimization method we observe best fit values for modulation amplitude and phase at 0.0092±0.0067 counts/keV/kg/day and 127.2±45.9 days, respectively.

115 citations

Journal ArticleDOI
05 Dec 2018-Nature
TL;DR: In this paper, the COSINE-100 experiment was used to determine whether there is evidence for an excess of events above the expected background in sodium iodide and to look for evidence of an annual modulation.
Abstract: Observations of galaxies and primordial radiation suggest that the Universe is made mostly of non-luminous dark matter1,2. Several new types of fundamental particle have been proposed as candidates for dark matter3, such as weakly interacting massive particles (WIMPs)4,5. These particles would be expected to interact with nuclei in suitable detector materials on Earth, for example, causing them to recoil. However, no definitive signal from such dark-matter interactions has been detected despite concerted efforts by many collaborations6. One exception is the much-debated claim by the DAMA collaboration of a statistically significant (more than nine standard deviations) annual modulation in the rate of nuclear interaction events. Annual modulation is expected because of the variation in Earth’s velocity relative to the Galaxy’s dark-matter halo that arises from Earth’s orbital motion around the Sun. DAMA observed a modulation in the rate of interaction events in their detector7,8,9 with a period and phase consistent with that expected for WIMPs10,11,12. Several groups have been working to develop experiments with the aim of reproducing DAMA’s results using the same target medium (sodium iodide)13,14,15,16,17. To determine whether there is evidence for an excess of events above the expected background in sodium iodide and to look for evidence of an annual modulation, the COSINE-100 experiment uses sodium iodide as the target medium to carry out a model-independent test of DAMA’s claim. Here we report results from the initial operation of the COSINE-100 experiment related to the first task18,19. We observe no excess of signal-like events above the expected background in the first 59.5 days of data from COSINE-100. Assuming the so-called standard dark-matter halo model, this result rules out WIMP–nucleon interactions as the cause of the annual modulation observed by the DAMA collaboration20,21,22,23. The exclusion limit on the WIMP–sodium interaction cross-section is 1.14 × 10−40 cm2 for 10-GeV c−2 WIMPs at a 90% confidence level. The COSINE-100 experiment will continue to collect data for two more years, enabling a model-independent test of the annual modulation observed by the DAMA collaboration.

102 citations

Journal ArticleDOI
TL;DR: COSINE-100 as mentioned in this paper is a dark matter search experiment based on an array of low background NaI(Tl) crystals located at the Yangyang underground laboratory in China.
Abstract: COSINE is a dark matter search experiment based on an array of low background NaI(Tl) crystals located at the Yangyang underground laboratory. The assembly of COSINE-100 was completed in the summer of 2016 and the detector is currently collecting physics quality data aimed at reproducing the DAMA/LIBRA experiment that reported an annual modulation signal. Stable operation has been achieved and will continue for at least 2 years. Here, we describe the design of COSINE-100, including the shielding arrangement, the configuration of the NaI(Tl) crystal detection elements, the veto systems, and the associated operational systems, and we show the current performance of the experiment.

89 citations

Journal ArticleDOI
TL;DR: In this article, the authors report results from the initial operation of the COSINE-100 experiment, which uses sodium iodide as the target medium and is designed to carry out a model independent test of DAMA's claim.
Abstract: Observations of galaxies and primordial radiation suggest that the Universe is made mostly of non-luminous dark matter. Several types of new fundamental particles have been proposed as candidates for dark matter such as weakly interacting massive particles (WIMPs) but no definitive signal has been seen despite concerted efforts by many collaborations. One exception is the much-debated claim by the DAMA collaboration of a statistically significant annual modulation in the event rate of their experiment with a period and phase consistent with that expected from WIMP dark matter. Several groups have been working to develop experiments with the aim of reproducing DAMA's results using the same target medium. Here we report results from the initial operation of the COSINE-100 experiment. COSINE-100 uses sodium iodide as the target medium-the same medium as DAMA-and is designed to carry out a model-independent test of DAMA's claim. Initial data based on the first 59.5 days indicate that there is no excess of events over the expected background, confirming that DAMA's annual modulation signal is in severe tension with results from other experiments under the assumption of dark matter having spin independent interactions and the Standard Halo Model. COSINE-100 is now taking data to study the presence of dark matter-induced annual modulation in the event rate of the sodium iodide detectors.

70 citations


Cited by
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Journal ArticleDOI
TL;DR: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations.
Abstract: The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six $2.8\text{ }\text{ }{\mathrm{GW}}_{\mathrm{th}}$ reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is $0.920\ifmmode\pm\else\textpm\fi{}0.009(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.014(\mathrm{syst})$. From this deficit, we determine ${sin }^{2}2{\ensuremath{\theta}}_{13}=0.113\ifmmode\pm\else\textpm\fi{}0.013(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.019(\mathrm{syst})$ based on a rate-only analysis.

1,979 citations

Journal ArticleDOI
TL;DR: This paper focuses on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle and gives a mini-review of finite group theory.
Abstract: This is a review paper about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of see-saw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally, we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A₄, S₄ and Δ(96).

849 citations

Journal ArticleDOI
Sergey Alekhin, Wolfgang Altmannshofer1, Takehiko Asaka2, Brian Batell3, Fedor Bezrukov4, Kyrylo Bondarenko5, Alexey Boyarsky5, Ki-Young Choi6, Cristóbal Corral7, Nathaniel Craig8, David Curtin9, Sacha Davidson10, Sacha Davidson11, André de Gouvêa12, Stefano Dell'Oro, Patrick deNiverville13, P. S. Bhupal Dev14, Herbi K. Dreiner15, Marco Drewes16, Shintaro Eijima17, Rouven Essig18, Anthony Fradette13, Björn Garbrecht16, Belen Gavela19, Gian F. Giudice3, Mark D. Goodsell20, Mark D. Goodsell21, Dmitry Gorbunov22, Stefania Gori1, Christophe Grojean23, Alberto Guffanti24, Thomas Hambye25, Steen Honoré Hansen24, Juan Carlos Helo26, Juan Carlos Helo7, Pilar Hernández27, Alejandro Ibarra16, Artem Ivashko28, Artem Ivashko5, Eder Izaguirre1, Joerg Jaeckel29, Yu Seon Jeong30, Felix Kahlhoefer, Yonatan Kahn31, Andrey Katz3, Andrey Katz32, Andrey Katz33, Choong Sun Kim30, Sergey Kovalenko7, Gordan Krnjaic1, Valery E. Lyubovitskij34, Valery E. Lyubovitskij35, Valery E. Lyubovitskij36, Simone Marcocci, Matthew McCullough3, David McKeen37, Guenakh Mitselmakher38, Sven Moch39, Rabindra N. Mohapatra9, David E. Morrissey40, Maksym Ovchynnikov28, Emmanuel A. Paschos, Apostolos Pilaftsis14, Maxim Pospelov13, Maxim Pospelov1, Mary Hall Reno41, Andreas Ringwald, Adam Ritz13, Leszek Roszkowski, Valery Rubakov, Oleg Ruchayskiy24, Oleg Ruchayskiy17, Ingo Schienbein42, Daniel Schmeier15, Kai Schmidt-Hoberg, Pedro Schwaller3, Goran Senjanovic43, Osamu Seto44, Mikhail Shaposhnikov17, Lesya Shchutska38, J. Shelton45, Robert Shrock18, Brian Shuve1, Michael Spannowsky46, Andrew Spray47, Florian Staub3, Daniel Stolarski3, Matt Strassler33, Vladimir Tello, Francesco Tramontano48, Anurag Tripathi, Sean Tulin49, Francesco Vissani, Martin Wolfgang Winkler15, Kathryn M. Zurek50, Kathryn M. Zurek51 
Perimeter Institute for Theoretical Physics1, Niigata University2, CERN3, University of Connecticut4, Leiden University5, Korea Astronomy and Space Science Institute6, Federico Santa María Technical University7, University of California, Santa Barbara8, University of Maryland, College Park9, Claude Bernard University Lyon 110, University of Lyon11, Northwestern University12, University of Victoria13, University of Manchester14, University of Bonn15, Technische Universität München16, École Polytechnique Fédérale de Lausanne17, Stony Brook University18, Autonomous University of Madrid19, University of Paris20, Centre national de la recherche scientifique21, Moscow Institute of Physics and Technology22, Autonomous University of Barcelona23, University of Copenhagen24, Université libre de Bruxelles25, University of La Serena26, University of Valencia27, Taras Shevchenko National University of Kyiv28, Heidelberg University29, Yonsei University30, Princeton University31, University of Geneva32, Harvard University33, Tomsk Polytechnic University34, University of Tübingen35, Tomsk State University36, University of Washington37, University of Florida38, University of Hamburg39, TRIUMF40, University of Iowa41, University of Grenoble42, International Centre for Theoretical Physics43, Hokkai Gakuen University44, University of Illinois at Urbana–Champaign45, Durham University46, University of Melbourne47, University of Naples Federico II48, York University49, University of California, Berkeley50, Lawrence Berkeley National Laboratory51
TL;DR: It is demonstrated that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.
Abstract: This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, $\tau \to 3\mu $ and to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals—scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.

842 citations

Journal ArticleDOI
Fengpeng An1, Guangpeng An, Qi An2, Vito Antonelli3  +226 moreInstitutions (55)
TL;DR: The Jiangmen Underground Neutrino Observatory (JUNO) as mentioned in this paper is a 20kton multi-purpose underground liquid scintillator detector with the determination of neutrino mass hierarchy (MH) as a primary physics goal.
Abstract: The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy (MH) as a primary physics goal. The excellent energy resolution and the large fiducial volume anticipated for the JUNO detector offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. In this document, we present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. Following an introduction summarizing the current status and open issues in neutrino physics, we discuss how the detection of antineutrinos generated by a cluster of nuclear power plants allows the determination of the neutrino MH at a 3–4σ significance with six years of running of JUNO. The measurement of antineutrino spectrum with excellent energy resolution will also lead to the precise determination of the neutrino oscillation parameters ${\mathrm{sin}}^{2}{\theta }_{12}$, ${\rm{\Delta }}{m}_{21}^{2}$, and $| {\rm{\Delta }}{m}_{{ee}}^{2}| $ to an accuracy of better than 1%, which will play a crucial role in the future unitarity test of the MNSP matrix. The JUNO detector is capable of observing not only antineutrinos from the power plants, but also neutrinos/antineutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, and solar neutrinos. As a result of JUNO's large size, excellent energy resolution, and vertex reconstruction capability, interesting new data on these topics can be collected. For example, a neutrino burst from a typical core-collapse supernova at a distance of 10 kpc would lead to ∼5000 inverse-beta-decay events and ∼2000 all-flavor neutrino–proton ES events in JUNO, which are of crucial importance for understanding the mechanism of supernova explosion and for exploring novel phenomena such as collective neutrino oscillations. Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of ∼400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the ${\theta }_{23}$ mixing angle. Detection of the (7)Be and (8)B solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with ${10}^{-5}\,{{\rm{eV}}}^{2}\lt {\rm{\Delta }}{m}_{41}^{2}\lt {10}^{-2}\,{{\rm{eV}}}^{2}$ and a sufficiently large mixing angle ${\theta }_{14}$ could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics. Examples include the search for proton decay via the $p\to {K}^{+}+\bar{ u }$ decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe.

807 citations

Journal ArticleDOI
TL;DR: In this article, a global analysis of neutrino oscillation data was performed, including high-precision measurements of the mixing angle at reactor experiments, which confirmed previous indications in favor of the neutrinos' mixing angle.
Abstract: We perform a global analysis of neutrino oscillation data, including high-precision measurements of the neutrino mixing angle ${\ensuremath{\theta}}_{13}$ at reactor experiments, which have confirmed previous indications in favor of ${\ensuremath{\theta}}_{13}g0$. Recent data presented at the Neutrino 2012 conference are also included. We focus on the correlations between ${\ensuremath{\theta}}_{13}$ and the mixing angle ${\ensuremath{\theta}}_{23}$, as well as between ${\ensuremath{\theta}}_{13}$ and the neutrino $CP$-violation phase $\ensuremath{\delta}$. We find interesting indications for ${\ensuremath{\theta}}_{23}l\ensuremath{\pi}/4$ and possible hints for $\ensuremath{\delta}\ensuremath{\sim}\ensuremath{\pi}$, with no significant difference between normal and inverted mass hierarchy.

751 citations