0000000000972129

AUTHOR

G. Lamanna

showing 37 related works from this author

The data acquisition system for the ANTARES neutrino telescope

2006

The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described.

Nuclear and High Energy Physics[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]Physics::Instrumentation and DetectorsData managementAstrophysics::High Energy Astrophysical PhenomenaNeutrino telescopeComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONFOS: Physical sciencesAstrophysics01 natural sciences[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]Data filteringData acquisition0103 physical sciences14. Life underwaterElectronics010306 general physicsInstrumentationdata acquisition system; neutrino telescopeRemote sensingAstroparticle physicsPhysicsneutrino telescope data acquisition system[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]010308 nuclear & particles physicsbusiness.industryDetectorAstrophysics (astro-ph)Astrophysics::Instrumentation and Methods for AstrophysicsAstronomyneutrino telescopedata acquisition systemComputer data storageFísica nuclearbusiness
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Precision measurement of the ratio BR(KS→π+π−e+e−)/BR(KL→π+π−πD0)

2011

Abstract The K S → π + π − e + e − decay mode was investigated using the data collected in 2002 by the NA48/1 Collaboration. With about 23 k K S → π + π − e + e − events and 59 k K L → π + π − π D 0 normalization decays, the K S → π + π − e + e − branching ratio relative to the K L → π + π − π D 0 one was determined to be BR ( K S → π + π − e + e − ) / BR ( K L → π + π − π D 0 ) = ( 3.28 ± 0.06 stat ± 0.04 syst ) × 10 − 2 . This result was used to set the upper limit | g E1 / g BR | 3.0 at 90% CL on the presence, in the decay amplitude, of an E1 direct emission ( g E1 ) term relative to the dominant inner bremsstrahlung ( g BR ) term. The CP-violating asymmetry A ϕ in the sin ϕ cos ϕ distri…

PhysicsNuclear and High Energy PhysicsAngular distribution010308 nuclear & particles physicsBranching fraction0103 physical sciencesBremsstrahlungPiAnalytical chemistryCP violation010306 general physics01 natural sciencesPhysics Letters B
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Empirical parameterization of the K±→π±π0π0 decay Dalitz plot

2010

As first observed by the NA48/2 experiment at the CERN SPS, the π0π0 invariant mass (M00) distribution from K±→π±π0π0 decay shows a cusp-like anomaly at M00=2m+, where m+ is the charged pion mass. An analysis to extract the ππ scattering lengths in the isospin I=0 and I=2 states, a0 and a2, respectively, has been recently reported. In the present work the Dalitz plot of this decay is fitted to a new empirical parameterization suitable for practical purposes, such as Monte Carlo simulations of K±→π±π0π0 decays.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsScatteringMonte Carlo methodDalitz plot01 natural sciencesPionIsospin0103 physical sciencesQuasinormal modeHigh Energy Physics::ExperimentInvariant massAnomaly (physics)Nuclear Experiment010306 general physicsPhysics Letters B
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A new measurement of the K±→π±γγ decay at the NA48/2 experiment

2014

Abstract The NA48/2 experiment at CERN collected two data samples with minimum bias trigger conditions in 2003 and 2004. A measurement of the rate and dynamic properties of the rare decay K ± → π ± γ γ from these data sets based on 149 decay candidates with an estimated background of 15.5 ± 0.7 events is reported. The model-independent branching ratio in the kinematic range z = ( m γ γ / m K ) 2 > 0.2 is measured to be B MI ( z > 0.2 ) = ( 0.877 ± 0.089 ) × 10 − 6 , and the branching ratio in the full kinematic range assuming a particular Chiral Perturbation Theory description to be B ( K π γ γ ) = ( 0.910 ± 0.075 ) × 10 − 6 .

Nuclear physicsPhysicsNuclear and High Energy PhysicsParticle decayPionChiral perturbation theoryMesonBranching fractionHadronAnalytical chemistryRadioactive decayDimensionless quantityPhysics Letters B
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The ANTARES Optical Beacon System

2007

ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirabl…

Nuclear and High Energy PhysicsPhotomultiplierPhysics::Instrumentation and Detectors[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]Astrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesneutrino telescope; optical beacon; time calibrationAstrophysics01 natural scienceslaw.inventionTelescope[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]Opticslaw0103 physical sciencesCalibrationtime calibrationAngular resolution14. Life underwateroptical beacon010306 general physicsInstrumentationCherenkov radiationPhysics[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]neutrino telescope time calibration optical beacon010308 nuclear & particles physicsbusiness.industryDetectorAstrophysics (astro-ph)Astrophysics::Instrumentation and Methods for Astrophysicsneutrino telescopeSITEAstronomyBeaconLIGHTFísica nuclearNeutrinobusiness
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Measurement of the branching ratios of the decays Ξ0→Σ+e−ν¯e and Ξ0¯→Σ+¯e+νe

2007

Abstract From 56 days of data taking in 2002, the NA48/1 experiment observed 6316 Ξ 0 → Σ + e − ν ¯ e candidates (with the subsequent Σ + → p π 0 decay) and 555 Ξ 0 ¯ → Σ + ¯ e + ν e candidates with background contamination of 215 ± 44 and 136 ± 8 events, respectively. From these samples, the branching ratios BR ( Ξ 0 → Σ + e − ν ¯ e ) = ( 2.51 ± 0.03 stat ± 0.09 syst ) × 10 −4 and BR ( Ξ 0 ¯ → Σ + ¯ e + ν e ) = ( 2.55 ± 0.14 stat ± 0.10 syst ) × 10 −4 were measured allowing the determination of the CKM matrix element | V us | = 0.209 −0.028 +0.023 . Using the Particle Data Group average for | V us | obtained in semileptonic kaon decays, we measured the ratio g 1 / f 1 = 1.20 ± 0.05 of the …

Nuclear physicsPhysicsNuclear and High Energy Physics010308 nuclear & particles physicsCabibbo–Kobayashi–Maskawa matrix0103 physical sciencesSigmaParticle Data Group010306 general physicsBranching (polymer chemistry)01 natural sciencesPhysics Letters B
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Observation of the rare decay K-S -> pi(0)e(+)e(-)

2003

A search for the decay Ks->pi0e+e- has been made by the NA48/1 experiment at the CERN SPS accelerator. Using data collected during 89 days in 2002 with a high-intensity Ks beam, 7 events were found with a background of 0.15 events. The branching fraction BR(Ks->pi0e+e-, m(ee) > 0.165 GeV/c^2) = (3.0^{+1.5}_{-1.2}(stat) +/-0.2 (syst)) x 10^{-9} has been measured. Using a vector matrix element and a form factor equal to one, the measurement gives BR(Ks->pi0e+e-) = (5.8^{+2.9}_{-2.4}) x 10^{-9}.

mesoni K; decadimenti rariPhysicsNuclear and High Energy Physics010308 nuclear & particles physicsBranching fractionK-LForm factor (quantum field theory)Analytical chemistryKAON DECAYS01 natural sciences3. Good healthHigh Energy Physics - Experimentmesoni Kdecadimenti rariCP VIOLATION; KAON DECAYS; K-L; SEARCHSEARCH0103 physical sciencesMatrix elementCP VIOLATIONAtomic physics010306 general physics
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Searches for lepton number violating $K^+$ decays

2019

The NA62 experiment at CERN reports a search for the lepton number violating decays K+ -> pi(-)e(+)e(+) and K+ -> pi(-)mu(+)mu(+) using a data sample collected in 2017. No signals are observed, and upper limits on the branching fractions of these decays of 2.2 x 10(-10) and 4.2 x 10(-11) are obtained, respectively, at 90% confidence level. These upper limits improve on previously reported measurements by factors of 3 and 2, respectively.

branching ratio: upper limitK+: rare decayNA62 experiment01 natural sciencesNA62Settore FIS/04 - Fisica Nucleare e SubnucleareHigh Energy Physics - Experimentelectron: pair productionHigh Energy Physics - Experiment (hep-ex)EconomicaK+: branching ratio[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]K meson decayPhysicsLarge Hadron ColliderElectroweak interactionlcsh:QC1-999muon: pair productionlepton number violationK+: semileptonic decayK+: secondary beamParticle Physics - ExperimentNuclear and High Energy PhysicsParticle physicsCERN LabS010.46FOS: Physical scienceskaonsS010:Desig=46K+ --> pi- 2muon+Partícules (Física nuclear)PE2_2Violació CP (Física nuclear)0103 physical sciencesKaon decayslepton number violation K meson K meson decay010306 general physicslepton number: violationKaon decays Lepton Number Violationhep-ex010308 nuclear & particles physicsS010:Desig=19CERN SPSK mesonLepton numberK+ --> pi- electron positronKaon Physics; Lepton Flavour Violation; NA62S010.19lcsh:Physicsexperimental results
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Search for heavy neutrinos in K + → μ + ν μ decays

2017

The NA62 experiment recorded a large sample of K+→μ+νμ decays in 2007. A peak search has been performed in the reconstructed missing mass spectrum. In the absence of a signal, limits in the range 2×10−6 to 10−5 have been set on the squared mixing matrix element |Uμ4|2 between muon and heavy neutrino states, for heavy neutrino masses in the range 300–375 MeV/ c2 . The result extends the range of masses for which upper limits have been set on the value of |Uμ4|2 in previous production search experiments.

PhysicsNuclear and High Energy PhysicsRange (particle radiation)Particle physicsMuon010308 nuclear & particles physicsPhysics beyond the Standard ModelHeavy neutrinoNA62 experiment01 natural scienceslcsh:QC1-999Heavy neutrinos; Kaon decays; Nuclear and High Energy PhysicsNuclear physicsKaon decayHeavy neutrinos0103 physical sciencesMass spectrumKaon decaysNeutrinoHeavy neutrino010306 general physicslcsh:PhysicsMixing (physics)
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First results of the Instrumentation Line for the deep-sea ANTARES neutrino telescope

2006

In 2005, the ANTARES Collaboration deployed and operated at a depth of 2500 m a so-called Mini Instrumentation Line equipped with Optical Modules (MILOM) at the ANTARES site. The various data acquired during the continuous operation from April to December 2005 of the MILOM confirm the satisfactory performance of the Optical Modules, their front-end electronics and readout system, as well as the calibration devices of the detector. The in-situ measurement of the Optical Module time response yields a resolution better than 0.5 ns. The performance of the acoustic positioning system, which enables the spatial reconstruction of the ANTARES detector with a precision of about 10 cm, is verified. T…

Photomultiplierneutrino astronomy; photon detection; underwater detectorPositioning systemInstrumentationAstrophysics::High Energy Astrophysical PhenomenaNeutrino astronomy Underwater detector Photon detectionFOS: Physical sciencesAstrophysics01 natural sciencesneutrino astronomy[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]0103 physical sciencesCalibrationAngular resolution010306 general physicsRemote sensingAstroparticle physicsPhysicsunderwater detector[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]010308 nuclear & particles physicsDetectorAstrophysics (astro-ph)Astrophysics::Instrumentation and Methods for AstrophysicsAstronomySITEAstronomy and AstrophysicsLIGHTPHOTON DETECTIONNEUTRINO ASTRONOMYFísica nuclearUNDERWATER DETECTORNeutrino astronomy
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Search for direct CP violation in the decays K-+/- -> 3 pi(+/-)

2006

Abstract We report a measurement of the direct CP violation asymmetry parameter A g in charged kaon decays K ± → π ± π + π − by the NA48/2 experiment at the CERN SPS. The experiment has been designed not to be limited by systematics in the asymmetry measurement. Using 1.67 × 10 9 such decays collected during the 2003 run, the charge asymmetry in the Dalitz plot linear slope parameter g has been measured to be A g = ( 1.7 ± 2.9 ) × 10 −4 . The precision of the result is limited by the statistics used.

Particle physicsNuclear and High Energy Physicsmedia_common.quotation_subjectDalitz plotviolazione CPcharged K mesonAsymmetryNEUTRAL KAONNuclear physicsmesoni K; violazione CPmesoni KCHARGE ASYMMETRY; NEUTRAL KAON; PARAMETER; NA48CP-violation asymmetriesCHARGE ASYMMETRYmedia_commonPhysicsLarge Hadron ColliderK meson; CP violationCharge (physics)PARAMETERK mesonkaon decayCP violationNA48CP violationkaon decay; charged K meson; CP-violation asymmetries
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Measurement of the KL→e+e−e+e− decay rate

2005

Abstract The decay rate of the long-lived neutral K meson into the e + e − e + e − final state has been measured with the NA48 detector at the CERN SPS. Using data collected in 1998 and 1999, a total of 200 events has been observed with negligible background. This observation corresponds to a branching ratio of Br ( K L → e + e − e + e − ) = ( 3.30 ± 0.24 stat ± 0.23 syst ± 0.10 norm ) × 10 −8 .

PhysicsNuclear and High Energy PhysicsMesonBranching fractionAnalytical chemistryAtomic physicsPositron annihilationPhysics Letters B
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Search for heavy neutral lepton production in K+ decays to positrons

2020

A search for heavy neutral lepton ($N$) production in $K^+\to e^+N$ decays using the data sample collected by the NA62 experiment at CERN in 2017--2018 is reported. Upper limits of the extended neutrino mixing matrix element $|U_{e4}|^2$ are established at the level of $10^{-9}$ over most of the accessible heavy neutral lepton mass range 144--462 MeV/$c^2$, with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The $|U_{e4}|^2$ range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/$c^2$.

AstrofísicaNuclear and High Energy PhysicsHeavy neutral lepton kaon meson kaon decay positronPontecorvo–Maki–Nakagawa–Sakata matrixSocio-culturaleFOS: Physical sciencesNA62 experiment7. Clean energy01 natural sciencesNA62High Energy Physics - ExperimentNuclear physicsHigh Energy Physics - Experiment (hep-ex)Positronkaon decays heavy neutral lepton SM extensionsPE2_2Big Bang nucleosynthesisSM extensionskaon physics0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]010306 general physicsComputingMilieux_MISCELLANEOUSPhysicsRange (particle radiation)Large Hadron Colliderkaon decays010308 nuclear & particles physicshep-exSettore FIS/04Heavy neutral leptonlepton flavour violationFísicalcsh:QC1-999kaon mesonkaon decaykaon physics; lepton flavour violation; NA62positronProduction (computer science)High Energy Physics::Experimentkaonlcsh:PhysicsParticle Physics - ExperimentLepton
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A measurement of the CP-conserving component of the decay KS0→π+π−π0

2005

Abstract The NA48 Collaboration has measured the amplitude of the CP-conserving component of the decay K S 0 → π + π − π 0 relative to K L 0 → π + π − π 0 . For the characteristic parameter λ , the values Re λ = 0.038 ± 0.010 and Im λ = − 0.013 ± 0.007 have been extracted. These values agree with earlier measurements and with theoretical predictions from chiral perturbation theory.

PhysicsNuclear and High Energy PhysicsAngular momentumAmplitudeChiral perturbation theory010308 nuclear & particles physicsComponent (thermodynamics)Quantum mechanics0103 physical sciencesPiPerturbation theory010306 general physics01 natural sciencesPhysics Letters B
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First observation and branching fraction and decay parameter measurements of the weak radiative decay Xi0 -> Lambda e+ e-

2007

The weak radiative decay Xi0 --> Lambda e+e- has been detected for the first time. We find 412 candidates in the signal region, with an estimated background of 15 +/- 5 events. We determine the branching fraction B(Xi0 --> Lambda e+e-) = [7.6 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(norm)] x 10^{-6}, consistent with an internal bremsstrahlung process, and the decay asymmetry parameter alpha_{XiLambdaee} = -0.8 +/- 0.2, consistent with that of Xi0 --> Lambda gamma. The charge conjugate reaction Xi0_bar --> Lambda_bar e+e- has also been observed.

Nuclear and High Energy Physicsmedia_common.quotation_subjectSignal regionRadiative decayXi0 hyperonAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencesAsymmetryiperoniacceleratori di particelleNOHigh Energy Physics - Experimentmesoni K0103 physical sciences010306 general physicsXi0 hyperon; radiative decayparticelle elementarimedia_commonPhysicsdecadimenti010308 nuclear & particles physicsBranching fractionradiative decayHigh Energy Physics::PhenomenologyBremsstrahlungmesoni K; iperoni; decadimenti; particelle elementari; acceleratori di particelleHigh Energy Physics::ExperimentAtomic physicsParticle Physics - ExperimentConjugate
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Measurement of the branching ratio of the decay Ξ0→Σ+μ−ν¯μ

2013

Abstract From the 2002 data taking with a neutral kaon beam extracted from the CERN-SPS, the NA48/1 experiment observed 97 Ξ 0 → Σ + μ − ν ¯ μ candidates with a background contamination of 30.8 ± 4.2 events. From this sample, the BR ( Ξ 0 → Σ + μ − ν ¯ μ ) is measured to be ( 2.17 ± 0.32 stat ± 0.17 syst ) × 10 − 6 .

PhysicsNuclear and High Energy PhysicsMeson010308 nuclear & particles physicsBranching fractionHadronAnalytical chemistryElementary particle01 natural sciencesNuclear physics0103 physical sciences010306 general physicsBosonDimensionless quantityPhysics Letters B
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First observation and measurement of the decay K±→π±e+e−γ

2008

Abstract Using the full data set of the NA48/2 experiment, the decay K ± → π ± e + e − γ is observed for the first time, selecting 120 candidates with 7.3 ± 1.7 estimated background events. With K ± → π ± π D 0 as normalisation channel, the branching ratio is determined in a model-independent way to be Br ( K ± → π ± e + e − γ , m e e γ > 260  MeV / c 2 ) = ( 1.19 ± 0.12 stat ± 0.04 syst ) × 10 −8 . This measured value and the spectrum of the e + e − γ invariant mass allow a comparison with predictions of chiral perturbation theory.

PhysicsNuclear and High Energy PhysicsAntiparticleChiral perturbation theoryMeson010308 nuclear & particles physicsBranching fractionHadronAnalytical chemistry01 natural sciencesNuclear physicsParticle decayPion0103 physical sciences010306 general physicsDimensionless quantityPhysics Letters B
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NA48/62 latest results

2017

The NA62 experiment at the CERN SPS recorded in 2007 a large sample of K+ ? µ+?µ decays. A peak search in the missing mass spectrum of this decay is performed. In the absence of observed signal, the limits obtained on B(K+ ? µ+?h) and on the mixing matrix element |Uµ 4| are reported. The upgraded NA62 experiment started data taking in 2015. About 5×1011K+ decays have been recorded so far to measure the branching ratio of the K+ ? ?+?? decay. Preliminary results from the K+ ? ?+?? analysis based on about 5% of the 2016 statistics are reported.

Nuclear physicsPhysicsParticle physicsBranching fractionTheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITYMass spectrumMatrix elementCreative commonsNA62 experimentParticle Physics - ExperimentSettore FIS/04 - Fisica Nucleare e SubnucleareLarge sample
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Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation

2021

Full list of authors: Abdalla, H.; Abe, H.; Acero, F.; Acharyya, A.; Adam, R.; Agudo, I; Aguirre-Santaella, A.; Alfaro, R.; Alfaro, J.; Alispach, C.; Aloisio, R.; Batista, R. Alves; Amati, L.; Amato, E.; Ambrosi, G.; Anguner, E. O.; Araudo, A.; Armstrong, T.; Arqueros, F.; Arrabito, L.; Asano, K.; Ascasibar, Y.; Ashley, M.; Backes, M.; Balazs, C.; Balbo, M.; Balmaverde, B.; Baquero Larriva, A.; Martins, V. Barbosa; Barkov, M.; Baroncelli, L.; de Almeida, U. Barres; Barrio, J. A.; Batista, P-, I; Becerra Gonzalez, J.; Becherini, Y.; Beck, G.; Tjus, J. Becker; Belmont, R.; Benbow, W.; Bernardini, E.; Berti, A.; Berton, M.; Bertucci, B.; Beshley, V; Bi, B.; Biasuzzi, B.; Biland, A.; Bissaldi, …

Gamma ray AstronomyCherenkov Telescope ArrayaxionsMATÉRIA ESCURAredshift: dependenceAstronomyGamma ray experimentsgamma ray experimentsAstrophysics01 natural sciencesCosmologyObservatorycosmological model: parameter spacegamma ray experimentHigh Energy Astrophysical Phenomena (astro-ph.HE)astro-ph.HEPhysicsCherenkov telescopes ; IACT technique ; Gamma rays ; Cosmic raysnew physics4. EducationSettore FIS/01 - Fisica SperimentaleAstrophysics::Instrumentation and Methods for AstrophysicsGamma-ray astronomyviolation: Lorentz3. Good healthobservatoryExtragalactic background lightastro-ph.COaxion-like particlesFísica nuclearAstrophysics - High Energy Astrophysical PhenomenaAstrophysics - Cosmology and Nongalactic Astrophysicsgamma ray: propagationCosmology and Nongalactic Astrophysics (astro-ph.CO)Active galactic nucleusAxionsAstrophysics::High Energy Astrophysical PhenomenaDark matterFOS: Physical sciencesAstrophysics::Cosmology and Extragalactic Astrophysicsinvariance: Lorentzjet: relativisticdark matter: halo0103 physical sciencesactive galactic nuclei; gamma ray experiments; axions; extragalactic magnetic fieldsAGNBlazarbackground010308 nuclear & particles physicsFísicaAstronomy and AstrophysicssensitivityCherenkov Telescope Arrayaxionextragalactic magnetic fieldsactive galactic nuclei[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]absorptionstatisticalBlazarsTelescopes
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Design of the online PC farm for the high level trigger of the NA62 experiment at CERN

2012

We present a highly efficient data processing framework optimized for software based triggers of fixed-target HEP experiments with continuous data collection during burst time alternating with longer out-of-burst periods.

Data processingEngineeringLarge Hadron ColliderHigh level triggerSoftwarebusiness.industryAstrophysics::High Energy Astrophysical PhenomenabusinessNA62 experimentComputer hardwareContinuous data
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Search for the dark photon in π0 decays

2015

A sample of $1.69\times 10^7$ fully reconstructed $\pi^0\to\gamma e^+e^-$ decay candidates collected by the NA48/2 experiment at CERN in 2003--2004 is analysed to search for the dark photon ($A'$) production in the $\pi^0\to\gamma A'$ decay followed by the prompt $A'\to e^+e^-$ decay. No signal is observed, and an exclusion region in the plane of the dark photon mass $m_{A'}$ and mixing parameter $\varepsilon^2$ is established. The obtained upper limits on $\varepsilon^2$ are more stringent than the previous limits in the mass range $9~{\rm MeV}/c^2<m_{A'}<70~{\rm MeV}/c^2$. The NA48/2 sensitivity to the dark photon production in the $K^\pm\to\pi^\pm A'$ decay is also evaluated.

Nuclear and High Energy PhysicsDark matterKAON DECAYSSocio-culturaleAstronomy & Astrophysics01 natural sciencesDark photondark matterHigh Energy Physics - ExperimentPhysics Particles & FieldsNuclear physics0202 Atomic Molecular Nuclear Particle And Plasma Physics0103 physical sciencesdark matter meson decays010306 general physicsDETECTORPhysicsNuclear and High Energy Physics dark photon photon pion neutral pionneutral pionRange (particle radiation)Large Hadron ColliderScience & Technology010308 nuclear & particles physicsPhysicsphotonDark Photon; KAON DECAYSpionmeson decaysNuclear & Particles Physicslcsh:QC1-999Physics NuclearPhysical Sciencesdark photonFotoneHigh Energy Physics::ExperimentParticle Physics - Experimentlcsh:PhysicsHigh Energy Physics - Experiment; Dark Photon
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New measurement of the K±→π±μ+μ− decay

2011

Abstract A sample of 3120 K ± → π ± μ + μ − decay candidates with ( 3.3 ± 0.7 ) % background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a detailed study of the decay properties. The branching ratio was measured to be BR = ( 9.62 ± 0.25 ) × 10 − 8 . The form factor W ( z ) , where z = ( M μ μ / M K ) 2 , was parameterized according to several models. In particular, the slope of the linear form factor W ( z ) = W 0 ( 1 + δ z ) was measured to be δ = 3.11 ± 0.57 . Upper limits of 2.9 × 10 − 2 and 2.3 × 10 − 2 on possible charge asymmetry and forward–backward asymmetry were established at 90% CL. An upper limit BR ( K ± → π ∓ μ ± μ ± ) 1.1 × 10 − 9 was e…

PhysicsNuclear physicsNuclear and High Energy PhysicsParticle decayAntiparticleMuonPionMesonBranching fractionAnalytical chemistryLeptonDimensionless quantityPhysics Letters B
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Measurement of the polarization of the Ξ0 (Ξ0¯) hyperon beam by the NA48/1 experiment

2009

Abstract A total of 368 415 Ξ 0 → Λ π 0 and 31 171 Ξ 0 ¯ → Λ ¯ π 0 were selected from data recorded in the NA48/1 experiment during 2002 data taking. From this sample, the polarization of Ξ 0 and Ξ 0 ¯ hyperons was measured to be P Ξ 0 = − 0.102 ± 0.012 (stat) ± 0.008 (syst) and P Ξ 0 ¯ = − 0.01 ± 0.04 (stat) ± 0.008 (syst) . The dependence of P Ξ 0 on the Ξ 0 transverse momentum with respect to the primary proton beam is also presented. With the same data sample, the ratio of Ξ 0 ¯ and Ξ 0 fluxes in proton collisions at 400 GeV / c on a beryllium target was measured.

PhysicsNuclear and High Energy PhysicsMesonProton010308 nuclear & particles physicsHadronHyperon7. Clean energy01 natural sciencesXi baryonNuclear physicsBaryonPion0103 physical sciences010306 general physicsNucleonPhysics Letters B
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New precise measurements of the and decay asymmetries

2010

Abstract The decay asymmetries of the weak radiative hyperon decays Ξ 0 → Λ γ and Ξ 0 → Σ 0 γ have been measured with high precision using data of the NA48/1 experiment at CERN. From about 52 000 Ξ 0 → Λ γ and 15 000 Ξ 0 → Σ 0 γ decays, we obtain for the decay asymmetries α Ξ 0 → Λ γ = − 0.704 ± 0.019 stat ± 0.064 syst and α Ξ 0 → Σ 0 γ = − 0.729 ± 0.030 stat ± 0.076 syst , respectively. These results are in good agreement with previous experiments, but more precise.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHadronHyperonGamma rayElementary particleFermion01 natural sciencesNuclear physicsBaryonParticle decay0103 physical sciences010306 general physicsRadioactive decayPhysics Letters B
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Search for heavy neutral lepton production in K+ decays

2018

A search for heavy neutral lepton production in $K^+$ decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the $10^{-7}$ to $10^{-6}$ level are established on the elements of the extended neutrino mixing matrix $|U_{\ell 4}|^2$ ($\ell=e,\mu$) for heavy neutral lepton mass in the range $170-448~{\rm MeV}/c^2$. This improves on the results from previous production searches in $K^+$ decays, setting more stringent limits and extending the mass range.

Nuclear and High Energy PhysicsleptonPontecorvo–Maki–Nakagawa–Sakata matrixheavy neutral leptons neutrino mixingFOS: Physical sciencesk mesonNA62 experiment01 natural sciencesneutrino mixingSettore FIS/04 - Fisica Nucleare e SubnuclearedecayHigh Energy Physics - ExperimentNuclear physicsneutrinoHigh Energy Physics - Experiment (hep-ex)Minimum biasEconomicaBounds; neutrinos; masses; testsTheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY0103 physical sciencesheavy neutral leptonslepton k meson decay neutrino010306 general physicsNuclear ExperimentPhysicsRange (particle radiation)Large Hadron Collider010308 nuclear & particles physicshep-exHigh Energy Physics::PhenomenologyAmbientalelcsh:QC1-999High Energy Physics::Experimentlcsh:PhysicsParticle Physics - ExperimentLepton
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Search for direct CP-violation in K±→π±π0π0 decays

2006

Abstract A search for direct CP-violation in K ± → π ± π 0 π 0 decay based on 47.14 million events has been performed by the NA48/2 experiment at the CERN SPS. The asymmetry in the Dalitz plot linear slopes A g = ( g + − g − ) / ( g + + g − ) is measured to be A g = ( 1.8 ± 2.6 ) × 10 −4 . The design of the experiment and the method of analysis provide good control of instrumental charge asymmetries in this measurement. The precision of the result is limited by statistics and is almost one order of magnitude better than that of previous measurements by other experiments.

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron Collidermedia_common.quotation_subjectPiCP violationDalitz plotCharge (physics)Good controlAsymmetryOrder of magnitudemedia_commonPhysics Letters B
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Search for Lepton Number and Flavor Violation in K+ and π0 Decays

2021

Searches for the lepton number violating $K^{+} \rightarrow \pi^{-} \mu^{+} e^{+}$ decay and the lepton flavour violating $K^{+} \rightarrow \pi^{+} \mu^{-} e^{+}$ and $\pi^{0} \rightarrow \mu^{-} e^{+}$ decays are reported using data collected by the NA62 experiment at CERN in $2017$-$2018$. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: $\mathcal{B}(K^{+}\rightarrow\pi^{-}\mu^{+}e^{+})<4.2\times 10^{-11}$, $\mathcal{B}(K^{+}\rightarrow\pi^{+}\mu^{-}e^{+})<6.6\times10^{-11}$ and $\mathcal{B}(\pi^{0}\rightarrow\mu^{-}e^{+})<3.2\times 10^{-10}$. These results improve by one order of magnitude over previous results for thes…

PhysicsParticle physics010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyFlavourGeneral Physics and Astronomy01 natural sciencesLepton number0103 physical sciencesPiHigh Energy Physics::Experiment010306 general physicsLeptonPhysical Review Letters
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Study of the K±→π±γγ decay by the NA62 experiment

2014

Abstract A study of the dynamics of the rare decay K ± → π ± γ γ has been performed on a sample of 232 decay candidates, with an estimated background of 17.4 ± 1.1 events, collected by the NA62 experiment at CERN in 2007. The results are combined with those from a measurement conducted by the NA48/2 Collaboration at CERN. The combined model-independent branching ratio in the kinematic range z = ( m γ γ / m K ) 2 > 0.2 is B MI ( z > 0.2 ) = ( 0.965 ± 0.063 ) × 10 − 6 , and the combined branching ratio in the full kinematic range assuming a Chiral Perturbation Theory description is B ( K π γ γ ) = ( 1.003 ± 0.056 ) × 10 − 6 . A detailed comparison of the results with the previous measurements…

PhysicsNuclear and High Energy PhysicsParticle decayPionChiral perturbation theoryNuclear magnetic resonanceMesonBranching fractionHadronAnalytical chemistryElementary particleDimensionless quantityPhysics Letters B
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Test of lepton flavour universality in K+→ℓ+ν decays

2011

Abstract A precision test of lepton flavour universality has been performed by measuring the ratio R K of kaon leptonic decay rates K + → e + ν and K + → μ + ν in a sample of 59 813 reconstructed K + → e + ν candidates with ( 8.71 ± 0.24 ) % background contamination. The result R K = ( 2.487 ± 0.013 ) × 10 − 5 is in agreement with the Standard Model expectation.

Nuclear physicsPhysicsNuclear and High Energy PhysicsParticle physicsFlavourWidth ratioUniversality (dynamical systems)LeptonPhysics Letters B
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

2021

Full list of authors: EHT MWL Science Working Group; Algaba, J. C.; Anczarski, J.; Asada, K.; Baloković, M.; Chandra, S.; Cui, Y. -Z.; Falcone, A. D.; Giroletti, M.; Goddi, C.; Hada, K.; Haggard, D.; Jorstad, S.; Kaur, A.; Kawashima, T.; Keating, G.; Kim, J. -Y.; Kino, M.; Komossa, S.; Kravchenko, E. V.; Krichbaum, T. P.; Lee, S. -S.; Lu, R. -S.; Lucchini, M.; Markoff, S.; Neilsen, J.; Nowak, M. A.; Park, J.; Principe, G.; Ramakrishnan, V.; Reynolds, M. T.; Sasada, M.; Savchenko, S. S.; Williamson, K. E.; Event Horizon Telescope Collaboration; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Anantua, Richard; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Barrett, John; Bintley, Dan; …

Accretion010504 meteorology & atmospheric sciencesAstronomyFluxAstrophysics7. Clean energy01 natural sciencesActive galactic nuclei; Radio cores; Low-luminosity active galactic nuclei; High energy astrophysics; Astrophysical black holes; Accretion; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Cosmology and Nongalactic Astrophysics; Astrophysics - Astrophysics of Galaxies010303 astronomy & astrophysicsHigh Energy Astrophysical Phenomena (astro-ph.HE)Physicsastro-ph.HERadio coreAccretion (meteorology)PhysicsAstrophysical black holes520 Astronomie und zugeordnete WissenschaftenActive galactic nuclei ; Radio cores ; Low-luminosity ; active galactic nuclei ; High energy astrophysics ; Astrophysical black holes ; AccretionAstrophysical black holeLow-luminosity active galactic nucleiastro-ph.COAstrophysics - High Energy Astrophysical PhenomenaAccretion; Active galactic nuclei; Astrophysical black holes; High energy astrophysics; Low-luminosity active galactic nuclei; Radio coresHigh energy astrophysicsRadio coresAstrophysics - Cosmology and Nongalactic AstrophysicsCosmology and Nongalactic Astrophysics (astro-ph.CO)Active galactic nucleusHigh-energy astronomyastro-ph.GAAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesF500Astrophysics::Cosmology and Extragalactic AstrophysicsHigh energy astrophysic0103 physical sciencesVery-long-baseline interferometryddc:530Astrophysics::Galaxy Astrophysics0105 earth and related environmental sciencesEvent Horizon TelescopeSupermassive black holeActive galactic nucleiAstronomy and Astrophysics530 PhysikAstrophysics - Astrophysics of GalaxiesGalaxySpace and Planetary ScienceAstrophysics of Galaxies (astro-ph.GA)ddc:520Active galactic nuclei; Radio cores; Low-luminosity active galactic nuclei; High energy astrophysics; Astrophysical black holes; AccretionHESS - Abteilung Hinton[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
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Precise measurement of the K±→π±e+e− decay

2009

Abstract A sample of 7253 K ± → π ± e + e − ( γ ) decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR = ( 3.11 ± 0.12 ) × 10 − 7 , where the uncertainty includes also the model dependence. The shape of the form factor W ( z ) , where z = ( M e e / M K ) 2 , was parameterized according to several models, and, in particular, the slope δ of the linear form factor W ( z ) = W 0 ( 1 + δ z ) was determined to be δ = 2.32 ± 0.18 . A possible CP violating asymmetry of K + and K − decay widths was investigated,…

Nuclear physicsPhysicsNuclear and High Energy PhysicsMesonBranching fractionHadronGamma rayAnalytical chemistryCP violationRadioactive decayLeptonDimensionless quantityPhysics Letters B
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Precision measurement of the ratio of the charged kaon leptonic decay rates

2013

A precision measurement of the ratio RK of the rates of kaon leptonic decays K+- --&gt; e nu and K+- --&gt; mu nu with the full data sample collected by the NA62 experiment at CERN in 2007-2008 is reported. The result, obtained by analysing ~150000 reconstructed K+- --&gt; e nu candidates with 11% background contamination, is RK = (2.488+-0.010)*10^{-5}, in agreement with the Standard Model expectation.

Nuclear and High Energy PhysicsParticle physicsstandard modelFOS: Physical sciencesNA62 experiment01 natural sciencesHigh Energy Physics - ExperimentStandard ModelNuclear physicsHigh Energy Physics - Experiment (hep-ex)lepton universalityRare kaon decays; chiral perturbation theoryLepton universality; Charged Kaon Decay0103 physical scienceskaon decays leptonic decays lepton universality010306 general physicschiral perturbation theoryPhysicsleptonic decaysLarge Hadron Colliderkaon decays010308 nuclear & particles physicscharged kaon3. Good healthCharged Kaon DecayRare kaon decaysKaon rare decaysFull dataKaon rare decays; branching ratio; charged kaon; leptonic decays; standard modelbranching ratioParticle Physics - ExperimentLepton universality
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Measurement of the Dalitz plot slope parameters of the K±→π±π+π− decay

2007

Abstract The distribution of the K ± → π ± π + π − decays in the Dalitz plot has been measured by the NA48/2 experiment at the CERN SPS with a sample of 4.71 × 10 8 fully reconstructed events. With the standard Particle Data Group parameterization the following values of the slope parameters were obtained: g = ( − 21.134 ± 0.017 ) % , h = ( 1.848 ± 0.040 ) % , k = ( − 0.463 ± 0.014 ) % . The quality and statistical accuracy of the data have allowed an improvement in precision by more than an order of magnitude, and are such as to warrant a more elaborate theoretical treatment, including pion–pion rescattering, which is in preparation.

PhysicsNuclear physicsNuclear and High Energy PhysicsDalitz plotParticle Data GroupAtomic physicsOrder of magnitudePhysics Letters B
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Search for heavy neutrinos at the NA48/2 and NA62 experiments at CERN

2018

© The Authors, published by EDP Sciences. The NA48/2 experiment at CERN has collected large samples of charged kaons decaying into a pion and two muons for the search of heavy nuetrinos. In addition, its successor NA62 has set new limits on the rate of charged kaon decay into a heavy neutral lepton (HNL) and a lepton, with = e, µ, using the data collected in 2007 and 2015. New limits on heavy neutrinos from kaon decays into pions, muons and positrons are presented in this report.

PhysicsParticle physicsLarge Hadron ColliderMuonPhysics::Instrumentation and Detectors010308 nuclear & particles physicsPhysicsQC1-999Nuclear TheoryHigh Energy Physics::PhenomenologyHeavy neutrino01 natural sciencesSettore FIS/04 - Fisica Nucleare e SubnuclearePhysics and Astronomy (all)Pion0103 physical sciencesHigh Energy Physics::ExperimentKaon decaysNeutrinoHeavy neutrinoNuclear Experiment010306 general physicsKaon decays Heavy neutrinoParticle Physics - ExperimentLepton
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First observation and study of the K± → π±π0e+e− decay

2018

The NA48/2 experiment at CERN reports the first observation of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay from an exposure of 1.7 x 10(11) charged kaon decays recorded in 2003-2004. A sample of 4919 candidates with 4.9% background contamination allows the determination of the branching ratio in the full kinematic region, BR(K-+/- -> pi(+/-)pi(0)e(+)e(-)) = (4.24 +/- 0.14) x 10(-6). The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on chiral perturbation theory. Several P- and CP-violating asymmetries are also evaluated.

rare decayNuclear and High Energy PhysicsChiral perturbation theoryCP violation; Monte-Carlo; searchAstronomy & AstrophysicsSpace (mathematics)quark mixing01 natural sciencesPartícules (Física nuclear)Charged Kaon decaysPhysics Particles & FieldsCharged Kaon decays quark mixing radiative kaon decay chiral perturbation theoryEconomica0202 Atomic Molecular Nuclear Particle And Plasma PhysicsViolació CP (Física nuclear)MONTE-CARLOSEARCH0103 physical sciencesKaon decaysradiative kaon decay010306 general physicsPhysicsScience & Technology010308 nuclear & particles physicsBranching fractionPhysicsKaon decays Chiral Perturbation TheoryAmbientaleK mesonNuclear & Particles PhysicsChiral Perturbation Theorylcsh:QC1-999fixed target experimentPhysics NuclearPhysical SciencesK meson rare decay fixed target experimentCP violationHigh Energy Physics::ExperimentCP VIOLATIONAtomic physicslcsh:PhysicsPhysics Letters B
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Search for K+→ π+νν¯ at NA62

2018

Flavour physics is one of the most powerful fields for the search of new physics beyond the Standard Model. The kaon sector with the rare decay K+ → π+νν̅ provides one of the cleanest and most promising channels. NA62, a fixed target experiment at the CERN SPS, aims to measure BR (K+ → π+νν̅) with 10% precision to test the Standard Model validity up to an energy scale of hundreds of TeV. NA62 had dedicated data taking for the K+ → π+νν̅ measurement in 2016 and 2017 and will continue in 2018. Here preliminary results on a fraction of 2016 dataset are presented. The analysis of the complete 2016 data sample is expected to achieve the SM sensitivity.

PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsPhysics beyond the Standard ModelPhysicsQC1-999Flavour Physicsrare Kaon decays01 natural sciencesMeasure (mathematics)Settore FIS/04 - Fisica Nucleare e SubnucleareStandard ModelPhysics and Astronomy (all)0103 physical sciences010306 general physicsFlavour Physics rare Kaon decays
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Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre

2021

Full list of authors: Acharyya, A.; Adam, R.; Adams, C.; Agudo, I.; Aguirre-Santaella, A.; Alfaro, R.; Alfaro, J.; Alispach, C.; Aloisio, R.; Alves Batista, R.; Amati, L.; Ambrosi, G.; Angüner, E. O.; Antonelli, L. A.; Aramo, C.; Araudo, A.; Armstrong, T.; Arqueros, F.; Asano, K.; Ascasíbar, Y. Ashley, M.; Balazs, C.; Ballester, O.; Baquero Larriva, A.; Barbosa Martins, V.; Barkov, M.; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.; Becerra, J.; Beck, G.; Becker Tjus, J.; Benbow, W.; Benito, M.; Berge, D.; Bernardini, E.; Bernlöhr, K.; Berti, A.; Bertucci, B.; Beshley, V.; Biasuzzi, B.; Biland, A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Blazek, J.; Bocchino, F.; Boisson, C.; Bonneau Arbe…

Cherenkov Telescope ArrayMATÉRIA ESCURAscale: TeVAstronomyatmosphere [Cherenkov counter]dark matter experimentDark matter theoryenergy resolutionGamma ray experimentsParticleAstrophysicscosmic background radiation01 natural sciences7. Clean energyHigh Energy Physics - Phenomenology (hep-ph)benchmarkWIMPHESSenergy: fluxTeV [scale]relativistic [charged particle]gamma ray experimentMAGIC (telescope)Monte CarloEvent reconstructionPhysicsHigh Energy Astrophysical Phenomena (astro-ph.HE)Contractionspatial distributiontrack data analysisPhysicsdensity [dark matter]ClumpyAstrophysics::Instrumentation and Methods for AstrophysicsimagingHigh Energy Physics - Phenomenologydark matter experiments; dark matter theory; gamma ray experiments; galaxy morphologyDark matter experimentsFísica nuclearVERITASAstrophysics - High Energy Astrophysical PhenomenaSimulationsnoiseWIMPAstrophysics::High Energy Astrophysical PhenomenaDark mattersatelliteCosmic background radiationFOS: Physical sciencesAnnihilationdark matter: densityAstrophysics::Cosmology and Extragalactic AstrophysicsCherenkov counter: atmosphereheavy [dark matter]530annihilation [dark matter]GLASTDark matter experiments; Dark matter theory; Galaxy morphology; Gamma ray experimentscosmic radiation [p]0103 physical sciencesCherenkov [radiation]Candidatesddc:530AGNCherenkov radiationRadiative Processesthermal [cross section]010308 nuclear & particles physicsFísicadark matter: annihilationGamma-Ray SignalsCherenkov Telescope Array ; dark matter ; Galactic Center ; TeV gamma-ray astronomyAstronomy and AstrophysicsMassCherenkov Telescope Arrayradiation: CherenkovsensitivityMAGICGalaxyAstronomíadark matter: heavygamma rayp: cosmic radiation[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph]correlationcharged particle: relativisticflux [energy]Galaxy morphology/dk/atira/pure/subjectarea/asjc/3100/3103galaxysupersymmetry[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]cross section: thermal
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