Y. Roh

Abstract The highest-energy known gamma-ray sources are all located within 0.°5 of extremely powerful pulsars. This raises the question of whether ultra-high-energy (UHE; >56 TeV) gamma-ray emission is a universal feature expected near pulsars with a high spin-down power. Using four years of data from the High Altitude Water Cherenkov Gamma-Ray Observatory, we present a joint-likelihood analysis of 10 extremely powerful pulsars to search for subthreshold UHE gamma-ray emission correlated with these locations. We report a significant detection (>3 σ ), indicating that UHE gamma-ray emission is a generic feature of powerful pulsars. We discuss the emission mechanisms of the gamma rays and the implications of this result. The individual environment, such as the magnetic field and particle density in the surrounding area, appears to play a role in the amount of emission.

The signals from high-Z scintillating crystals such as PbWO4 and BGO contain a significant Cherenkov component. We investigate methods to determine the contribution of Cherenkov light to the signals generated by high-energy electrons and pions (mips), both statistically and event-by-event. These methods are based on differences in the spectra, the time structure and/or the directionality of the two types of light. The electron signals, and their composition, are also analyzed as a function of the age (or depth) of the shower.

Results are presented of beam tests in which a small electromagnetic calorimeter consisting of lead tungstate crystals was exposed to 50 GeV electrons and pions. This calorimeter was backed up by the DREAM Dual-Readout calorimeter, which measures the scintillation and Cherenkov light produced in the shower development, using two different media. The signals from the crystal calorimeter were analyzed in great detail in an attempt to determine the contributions from these two types of light to the signals, event by event. This information makes it possible to eliminate the dominating source of fluctuations and thus achieve an important improvement in hadronic calorimeter performance.

We report on the response of the combined CMS electromagnetic (EB) and hadronic barrel (HB) calorimeters to hadrons, electrons and muons in a wide momentum range from 1 to 350 GeV/c. To our knowledge, this is the widest range of momenta in which any calorimeter system is studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. We analyze in detail the dierences in total calorimeter response to charged pions, kaons, protons and antiprotons and discuss the underlying phenomena. These data will play a crucial role in the thorough understanding of jets in CMS.

In recent years, short-form social media videos have emerged as an important source of health-related advice. In this study, we investigate whether experts or ordinary users in such videos are more effective in debunking the common misperception that talking about suicide should be avoided. We also explore a new trend on TikTok and other platforms, in which users attempt to back up their arguments by displaying scientific articles in the background of their videos. To test the effect of source type (expert vs. ordinary user) and scientific references (present or absent), we conducted a 2 × 2 between-subject plus control group experiment (n = 956). In each condition, participants were shown a TikTok video that was approximately 30 seconds long. Our findings show that in all four treatment groups, participants reduced their misperceptions on the topic. The expert was rated as being more authoritative on the topic compared to the ordinary user. However, the expert was also rated as being less credible compared to the ordinary user. The inclusion of a scientific reference did not make a difference. Thus, both experts and ordinary users may be similarly persuasive in a short-form video environment.

A minimal non-thermal dark matter model that can explain both the existence of dark matter and the baryon asymmetry in the universe is studied. It requires two color-triplet, iso-singlet scalars with $\mathcal{O}$(TeV) masses and a singlet Majorana fermion with a mass of $\mathcal{O}$(GeV). The fermion becomes stable and can play the role of the dark matter candidate. We consider the fermion to interact with a top quark via the exchange of QCD-charged scalar fields coupled dominantly to third generation fermions. The signature of a single top quark production associated with a bottom quark and large missing transverse momentum opens up the possibility to search for this type of model at the LHC in a way complementary to existing monotop searches.

Results are presented of detailed measurements of the signals generated by high-energy electrons and muons in lead tungstate crystals. A significant fraction of the light produced in these crystals and detected by photomultiplier tubes is the result of the Cherenkov mechanism. This is concluded from the angular dependence of the signals and from their time structure. Depending on the orientation of the crystals and on the particle type, Cherenkov light may account for up to 15% of the total signals.

The hadronic performance of a Dual-Readout calorimeter consisting of a crystal em section and a hadronic section read out with two types of optical fibers is studied with 200 GeV p þ .The em fraction of hadronic showers developing in this calorimeter system is determined event by event from the relative amounts of Cherenkov light and scintillation light produced in the shower development.Data are presented for two types of crystals (PbWO 4 and BGO), each of which offers unique opportunities in this respect.The information obtained with this technique may lead to an important improvement in the hadronic calorimeter performance.

Abstract The contributions of neutrons to hadronic signals from the DREAM calorimeter are measured by analyzing the time structure of these signals. This contribution is characterized by an exponential tail in the pulse shape, with a time constant of ∼ 20 ns . The relative contribution of neutrons to the signals is measured event by event. It is shown that this information can be used to improve the hadronic calorimeter performance.

The contributions of neutrons to hadronic signals from the DREAM calorimeter are measured by analyzing the time structure of these signals. The neutrons, which mainly originate from the evaporation stage of nuclear breakup in the hadronic shower development process, contribute through elastic scattering off protons in the plastic scintillating fibers which provide the dE/dx information in this calorimeter. This contribution is characterized by an exponential tail in the pulse shape, with a time constant of ∼25ns. The relative contribution of neutrons to the signals increases with the distance from the shower axis. As expected, the neutrons do not contribute to the DREAM Cherenkov signals.

The signals from lead tungstate crystals are studied as a function of temperature. Over the range from 13 to 45∘C, the total light output decreases by about a factor of two. This effect only concerns the scintillation component, so that the relative contribution of Cherenkov light to the signals increases with the same factor. The decay time of the scintillation component is observed to decrease as well.

Abstract Microquasars with high-mass companion stars are promising very high energy (VHE; 0.1–100 TeV) gamma-ray emitters, but their behaviors above 10 TeV are poorly known. Using the High Altitude Water Cerenkov (HAWC) observatory, we search for excess gamma-ray emission coincident with the positions of known high-mass microquasars (HMMQs). No significant emission is observed for LS 5039, Cyg X-1, Cyg X-3, and SS 433 with 1523 days of HAWC data. We set the most stringent limit above 10 TeV obtained to date on each individual source. Under the assumption that HMMQs produce gamma rays via a common mechanism, we have performed source-stacking searches, considering two different scenarios: (I) gamma-ray luminosity is a fraction ϵ γ of the microquasar jet luminosity, and (II) VHE gamma rays are produced by relativistic electrons upscattering the radiation field of the companion star in a magnetic field B . We obtain ϵ γ < 5.4 × 10 −6 for scenario I, which tightly constrains models that suggest observable high-energy neutrino emission by HMMQs. In the case of scenario II, the nondetection of VHE gamma rays yields a strong magnetic field, which challenges synchrotron radiation as the dominant mechanism of the microquasar emission between 10 keV and 10 MeV.

For the Heavy Ion Accelerator Project in South Korea we designed an optimized antimuon beamline by using a simulation with the G4beamline and the TRANSPORT software packages. This research suggests that the optimized muon beamline can transport 2.4×108 antimuons per second to a circle with a radius of 3 cm. In terms of the muon rate, this is competitive with world-leading muon beam facilities.

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The role and location of food manufacturers are crucial to regional economic sustainability and solving problems related to local employment.This study aims to create a foundation for future regional economic and alternative governmental policies by analyzing the factors that influence food manufacturing productivity in South Korea and reassessing their efficiency in the agricultural industry.This study uses a functional formula to select variables based on food manufacturer data and regional accomplishments.It then applies quantile regression analysis to measure the effects of labor productivity on food manufacturers at a regional level and prevent sample bias.The analysis results show that the impact of corporate elements is greater when the company is larger and permanent positions are more prevalent.Regarding regional characteristics, the horizontal link between industries, spatial agglomeration, and national government financing is influential, along with the local government financing policy.While little research has been conducted on the growth of Korean food manufacturers based on the unit of region, the significance of this study is that it focuses on various connections and agglomeration effects at the regional level and addresses the influence of regional characteristics.Based on the unit of region, this study identifies the factors that affect the labor productivity of food manufacturers while analyzing their effects.The scientific novelty of this paper lies in its analysis of the factors that influence food manufacturing productivity in South Korea and reassessment of their efficiency in the agricultural industry.This approach provides new insights into the growth of Korean food manufacturers based on the unit of region, given that the food manufacturing industry is closely related to the sustainability of the regional economy, the settlement of social issues, the protection of agriculture and farming areas, the fostering of small and medium-sized firms, and balanced regional development.

A large number of top quarks will be produced at the Large Hadron Collider (LHC) during the Run II period. This will allow us to measure the rare processes from the top sector in great details. We present a study of top-quark pair production in association with a bottom-quark pair ( $$t\bar tb\bar b$$ ) from fast simulations for the Compact Muon Solenoid (CMS) experiment. The differential distributions of $$t\bar tb\bar b$$ are compared with the top-quark pair production with two additional jets ( $$t\bar tjj$$ ) and with the production in association with the Higgs ( $$t\bar tH$$ ), where the Higgs decays to a bottom-quark pair. The significances of the $$t\bar tb\bar b$$ process in the dileptonic and the semileptonic decay modes are calculated with the data corresponding to an integrated luminosity of 10 fb-1, which is foreseen to be collected in the early Run II period. This study will provide an important input in searching for new physics beyond the standard model, as well as in searching for the $$t\bar tH$$ process where the Yukawa coupling with the top quark can be directly measured.

Results of detailed measurements of the Čerenkov light yield from lead tungstate (PbWO4) crystals are presented. A single crystal as well as a small homogeneous calorimeter (ECAL), consisting of 19 PbWO4 crystals, were exposed to electrons, muons and pions at the H4 beam line at CERN. It turns out that a significant fraction of the detected light is not the result of scintillation processes, but rather of the Čerenkov mechanism. This can be assessed from the analysis of both the angular dependence of the signals and their time structure. Detailed studies of the ECAL signals, corroborated by the measurements taken with the Dual-Readout calorimeter (DREAM), backing up the ECAL during beam tests, show that it is possible to estimate the independent contributions of scintillation and Čerenkov light. This information makes it possible to account for one of the dominant sources of fluctuations in hadronic showers and thus to achieve a significant improvement in hadronic calorimetry performance.

Microquasars with high-mass companion stars are promising very-high-energy (VHE; 0.1-100 TeV) gamma-ray emitters, but their behaviors above 10 TeV are poorly known. Using the High Altitude Water Cherenkov (HAWC) observatory, we search for excess gamma-ray emission coincident with the positions of known high-mass microquasars (HMMQs). No significant emission is observed for LS 5039, Cygnus X-1, Cygnus X-3, and SS 433 with 1,523 days of HAWC data. We set the most stringent limit above 10 TeV obtained to date on each individual source. Under the assumption that HMMQs produce gamma rays via a common mechanism, we have performed source-stacking searches, considering two different scenarios: I) gamma-ray luminosity is a fraction $\epsilon_\gamma$ of the microquasar jet luminosity, and II) very-high-energy gamma rays are produced by relativistic electrons up-scattering the radiation field of the companion star in a magnetic field $B$. We obtain $\epsilon_\gamma < 5.4\times 10^{-6}$ for scenario I, which tightly constrains models that suggest observable high-energy neutrino emission by HMMQs. In the case of scenario II, the non-detection of VHE gamma rays yields a strong magnetic field, which challenges synchrotron radiation as the dominant mechanism of the microquasar emission between 10 keV and 10 MeV.

Differential cross sections of top-quark pair production are measured in dilepton decay channel with proton-proton collisions at a center-of-mass energy of 13 TeV. The measurement is performed with a RunII data using CMS detector at the Large Hadron Collider. In this analysis, we measure the differential cross sections with respect to kinematic variables of leptons, bjets, and top-quarks. Presented at TOP2015 8th International Workshop on Top Quark Physics First measurement of differential cross sections for ttbar production in dilepton final state at 13 TeV collisions Youn ROH∗Korea University (KR) E-mail: youn.jung.roh@cern.ch on behalf of the CMS Collaboration Differential cross sections of top-quark pair production are measured in the dilepton decay channel with proton-proton collisions at a center-of-mass energy of 13 TeV. The measurement is performed with a Run II data using CMS detector at the Large Hadron Collider. In this analysis, we measure the differential cross sections with respect to kinematic variables of leptons, b jets, and top-quarks. 8th International Workshop on Top Quark Physics, TOP2015 14-18 September, 2015 Ischia, Italy

The large number of top quarks will be produced at the Large Hadron Collider for Run II period. This will allow us to measure the rare processes from the top sector in great details. We present the study of the top-quark-pair production in association with a bottom-quark pair (ttbb) from fast simulations for the CMS experiment. Differential distributions of ttbb are compared with the top-quark-pair production with two additional jets (ttjj) and also the production in association with the Higgs (ttH) where the Higgs decays to a bottom-quark pair. The significances of ttbb process in the dileptonic and semileptonic decay mode are calculated with the data corresponding to an integrated luminosity of 10 fb-1 which is foreseen to be collected in the early Run II period. This study will be an important input in searching for the new physics beyond the standard model as well as in searching for ttH process where the Yukawa coupling with the top quark can be directly measured.

The forward-backward asymmetry parameter ($A_{\rm FB}$) as a function of dilepton invariant mass in $Z / \gamma^* \rightarrow l^+l^-$ ($l$=$e$ or $\mu$) at $\sqrt{s}$=7 TeV is measured using 2.2 fb$^{-1}$ of $pp$ collision data in 2011. The uncorrected (raw) $A_{\rm FB}$ and the corrected (unfolded) $A_{\rm FB}$ is performed in a wide mass range between 40 GeV/$c^{2}$ to 1000 GeV/$c^{2}$, and comparative studies and correction techniques with simulation are described in detail. We measure raw $A_{\rm FB}$ for the first time in a large rapidity range of 3 $<|\eta| <$ 5 with electrons using the forward calorimeters and achieve almost non-diluted $A_{\rm FB}$ result. The $A_{\rm FB}$ measurements with muons and electrons and their combination are consistent with the Standard Model (SM) prediction within uncertainties.

The forward-backward asymmetry parameter (AFB) as a function of dilepton invariant mass in Z/γ* →l+l- (l=e or μ) at √s=7 TeV is measured using 2.2 fb-1 of pp collision data in 2011. The forward-backward asymmetry measurement is performed using muons within |η| < 2.1 and electrons within |η| < 2.4 in a wide mass range between 40 GeV/c2 to 1000 GeV/c2. The forward-backward asymmetry is also measured for the first time in a large rapidity range of |η| < 5 with electrons using the CMS forward calorimeters and results in a less diluted AFB measurement, as expected. The forward-backward asymmetry parameters are unfolded in three stages, limited pre-FSR, full pre-FSR, and non-diluted stage in order to obtain parton level AFB. The muon and electron results are combined, and the individual and combined results are found to be consistent with the Standard Model prediction within statistical and systematic uncertainties.

In dark photon search experiments with electron beam-dumps, it is difficult to access the smaller dark photon life-time region of phase space due to enormous backgrounds from low-energy particles emerging from the target. In order to reduce the background, a thick beam-dump target is usually necessary. We propose to detect the Cherenkov radiation in gas due to ultra-relativistic electron and positron from dark photon decay. The secondary particles emerging from the beam dump have very little chance to produce such Cherenkov radiation in gas. Making use of the direction of the Cherenkov radiation, low background dark photon search with thinner target is possible. This would allow one to access challenging regions of the dark photon parameter space with low power electron beams and low-cost experimental setup.

Differential cross sections of top-quark pair production are measured in the dilepton decay channel with proton-proton collisions at a center-of-mass energy of 13 TeV. The measurement is performed with Run II data using the CMS detector at the Large Hadron Collider. In this analysis, we measure the differential cross sections with respect to the kinematic variables of top-quarks at particle level.

This note describes a study of intermediate and heavy (masses considered 250, 300, 400, 500, 600 and 800 GeV/c) mass Higgs boson production via Weak Boson Fusion (WBF) using the CMS detector at LHC. Having the second largest production cross section, WBF is one of the main process, where the Higgs particle can be found. Evaluated LHC integrated luminosity should be more than 500 fb−1, when the mass of Higgs particle is expected to be in a range 250 400 GeV/c and more than 1000 fb−1 when mass of Higgs particle is expected to be in a range 500 1000 GeV/c. 1) e-mail: alexi.mestvirishvili@cern.ch

Purpose : Derived are the factors Korean companies must understand and the preparations they must make before entering the Chinese distribution market. Also examined is the influence of experience with the Chinese market on the level of understanding and preparation.&#x0D; Research design, data and methodology : There are four main research hypotheses. Each hypothesis is about the level of understanding and preparation, the experience needed before entering the market, and the decision-making process for entry. Multiple regression analysis tests the hypotheses.&#x0D; Results : The level of comprehension affected the level of readiness. Experience with the Chinese market influenced all factors. However, the type of hope for advancement was meaningless.&#x0D; Conclusions : This study identifies meaningful understanding of, and preparation factors for, entering the Chinese distribution market. In order to enter the Chinese retail market, market experience is more important than anything else, and it has a positive effect on other factors. It also has an impact on decision-making.

Measurements of normalized differential cross sections for top quark pair production are performed in the dilepton decay channels in proton-proton collisions at a center-of-mass energy of 13 TeV. The differential cross sections are measured with data corresponding to an integrated luminosity of 2.1 fb$^{-1}$ recorded by the CMS experiment at the LHC. We have measured the cross sections differentially as a function of the kinematic properties of the leptons (electron or muon), jets from bottom quark hadronization, top quarks, and top quark pairs at the particle and parton levels. The $t\bar{t}$ differential cross section measurements are compared to several Monte Carlo generators that implement calculations up to next-to-leading order in perturbative quantum chromodynamics interfaced with parton showering, and also to fixed-order theoretical calculations of top quark pair production beyond next-to-leading order accuracy.

on behalf of the CMS CollaborationDifferential measurements of top quark pair and single top quark (t-channel) production cross sections are presented using data collected by CMS at different center-of-mass energies.The cross sections are measured as a function of various kinematic observables of the top quarks and the jets and leptons of the event final state.The t t measurements are extended to the TeV range using jet substructure techniques to exploit the boosted regime.The results are confronted with precise theory calculations.

on behalf of the CMS CollaborationNormalized differential cross sections for top quark pair production are measured in the dilepton decay channels in proton-proton collisions at a center-of-mass energy of 13 TeV.The measurements are performed with data corresponding to an integrated luminosity of 2.2 fb -1 using the CMS detector at the LHC.The cross sections are measured differentially as a function of the kinematic properties of the leptons, jets from bottom quark hadronization, top quarks, and top quark pairs at the particle and parton levels.The results are compared to several Monte Carlo generators that implement calculations up to next-to-leading order in perturbative quantum chromodynamics interfaced with parton showering, and also to fixed-order theoretical calculations of top quark pair production up to next-to-next-to-leading order.

Measurements of normalized differential cross sections for top quark pair production are performed in the dilepton decay channels in proton-proton collisions at a center-of-mass energy of 13 TeV. The differential cross sections are measured with data corresponding to an integrated luminosity of 2.1 fb$^{-1}$ recorded by the CMS experiment at the LHC. We have measured the cross sections differentially as a function of the kinematic properties of the leptons (electron or muon), jets from bottom quark hadronization, top quarks, and top quark pairs at the particle and parton levels. The $t\bar{t}$ differential cross section measurements are compared to several Monte Carlo generators that implement calculations up to next-to-leading order in perturbative quantum chromodynamics interfaced with parton showering, and also to fixed-order theoretical calculations of top quark pair production beyond next-to-leading order accuracy.

Abstract The formation and growth of solid electrolyte interphase (SEI) are key parameters governing battery life prediction models of lithium-ion batteries (LiBs). However, as conventional battery life prediction models do not reflect other degradation parameters such as crack formation and propagation in high-nickel cathode materials, their accuracy is greatly reduced as the nickel content increases in layered oxide cathodes. Herein, we propose an advanced prediction model that includes both crack propagation and SEI growth. The reliability of this model was verified using experimental data of over 50 commercial 18650 LiB cells, which were tested under depths of discharge and current rates, from 500 to 5,000 cycles. The proposed model can predict capacity retention values with less than 5% error, even in real operations at energy storage systems and electric vehicles. This model can provide a standard solution for predicting the cycle life of LiBs with high-nickel layered cathodes.