Alan Coleman
A5026599729- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Gamma-ray bursts and supernovae
- High-Energy Particle Collisions Research
- Advanced Chemical Physics Studies
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Physics of Superconductivity and Magnetism
- Nuclear physics research studies
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Radio Wave Propagation Studies
- Precipitation Measurement and Analysis
- Cold Atom Physics and Bose-Einstein Condensates
- Radiation Detection and Scintillator Technologies
- Theoretical and Computational Physics
- Advanced Physical and Chemical Molecular Interactions
- Quantum and electron transport phenomena
- Photocathodes and Microchannel Plates
- Magnetism in coordination complexes
Uppsala University
2021-2024
Lawrence Berkeley National Laboratory
2023-2024
Southern University and Agricultural and Mechanical College
2021-2024
Clark Atlanta University
2021-2024
University of Alaska Anchorage
2021-2024
Providence College
2021-2024
The University of Texas at Arlington
2021-2024
University of Delaware
1992-2024
Institute of Astronomy and Space Physics
2016-2023
Universidad Nacional de La Plata
2016-2023
Abstract : A new approach is presented to the many-particle problem in quantum mechanics by proposing a method of finding natural orbitals and geminals system without prior knowledge wave function. It expounds hitherto unpublished results author's work. (Author
In an exclusive measurement of the reaction gammad-->K(+)K(-)pn, a narrow peak that can be attributed to exotic baryon with strangeness S=+1 is seen in K(+)n invariant mass spectrum. The at 1.542+/-0.005 GeV/c(2) measured width 0.021 FWHM, which largely determined by experimental resolution. statistical significance (5.2+/-0.6)sigma. and observed are consistent recent reports other groups.
We report a study of the distributions depth maximum, ${X}_{\mathrm{max}}$, extensive air-shower profiles with energies above $1{0}^{17.8}\text{ }\text{ }\mathrm{eV}$ as observed fluorescence telescopes Pierre Auger Observatory. The analysis method for selecting data sample minimal sampling bias is described in detail well experimental cross-checks and systematic uncertainties. Furthermore, we discuss detector acceptance resolution ${X}_{\mathrm{max}}$ measurement provide parametrizations...
This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate significance an astrophysical signal a looking for excess clustered events with energies typically above ∼1 TeV among background atmospheric muons neutrinos. perform full-sky scan, search within selected catalog, catalog population study, three stacked Galactic searches. The most significant point in northern hemisphere...
We present a combined fit of simple astrophysical model UHECR sources to both the energy spectrum and mass composition data measured by Pierre Auger Observatory. The has been performed for energies above 5 ⋅ 1018 eV, i.e. region all-particle so-called "ankle" feature. we adopted consists identical uniformly distributed in comoving volume, where nuclei are accelerated through rigidity-dependent mechanism. results suggest characterized relatively low maximum injection energies, hard spectra...
Using the data taken at Pierre Auger Observatory between December 2004 and 2012, we have examined implications of distributions depths atmospheric shower maximum (Xmax), using a hybrid technique, for composition hadronic interaction models. We do this by fitting with predictions from variety models variations in primary cosmic rays examining quality fit. Regardless what model is assumed, find that our are not well described mix protons iron nuclei over most energy range. Acceptable fits can...
The IceCube Neutrino Observatory has established the existence of a high-energy all-sky neutrino flux astrophysical origin. This discovery was made using events interacting within fiducial region detector surrounded by an active veto and with reconstructed energy above 60 TeV, commonly known as starting event sample, or HESE. We revisit analysis HESE sample additional 4.5 years data, newer glacial ice models, improved systematics treatment. paper describes in detail, reports on latest...
We report three searches for high energy neutrino emission from astrophysical objects using data recorded with IceCube between 2011 and 2020. Improvements over previous work include new reconstruction calibration methods. In one search, the positions of 110 a priori selected gamma-ray sources were analyzed individually possible surplus neutrinos atmospheric cosmic background expectations. found an excess $79_{-20}^{+22}$ associated nearby active galaxy NGC 1068 at significance 4.2$\,\sigma$....
Functions which can be expressed as an antisymmetrized power of a single two-particle function (a geminal) occur in the BCS ansatz. They constitute comparatively tractable generalization Slater determinant. The second-order reduced density matrix and bounds on its eigenvalues are obtained for most general such geminal (AGP). These physically great importance, being analogs, analysis wavefunction into pair states, one-particle occupation numbers independent-particle model. A necessary...
We present the first hybrid measurement of average muon number in air showers at ultra-high energies, initiated by cosmic rays with zenith angles between $62^\circ$ and $80^\circ$. The is based on 174 events recorded simultaneously Surface Detector array Fluorescence Pierre Auger Observatory. for each shower derived scaling a simulated reference profile lateral density distribution ground until it fits data. A $10^{19}$~eV angle $67^\circ$, which arrives an altitude 1450 m above sea level,...
Abstract A new analysis of the data set from Pierre Auger Observatory provides evidence for anisotropy in arrival directions ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative excess arrivals strong, nearby sources. The consist 5514 events above with zenith angles up to 80° recorded before 2017 April 30. Sky models have been created two distinct populations extragalactic gamma-ray emitters: active galactic nuclei second catalog hard Fermi -LAT sources (2FHL)...
We report on the first measurement of astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, neutrinos this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed sensitive energy range 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected Fermi-type acceleration high particles at sources. find spectral index be γ=2.53±0.07 normalization for each flavor...
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on absolute calibration, and apply it events with primary 6–16 EeV (ECM=110–170 TeV), whose longitudinal development lateral distribution were simultaneously measured by Pierre Auger Observatory. The average shower is 1.33±0.16 (1.61±0.21) times larger than predicted using leading LHC-tuned EPOS-LHC...
We analyze the distribution of arrival directions ultra-high energy cosmic rays recorded at Pierre Auger Observatory in 10 years operation. The data set, about three times larger than that used earlier studies, includes with zenith angles up to $80^\circ$, thus covering from $-90^\circ$ $+45^\circ$ declination. After updating fraction events correlating active galactic nuclei (AGNs) V\'eron-Cetty and V\'eron catalog, we subject energies excess 40 EeV different tests for anisotropy. search...
The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, has been a mystery for over century. Due to deflection in interstellar magnetic fields, rays from the Milky Way arrive at Earth random directions. However, near their sources and during propagation, interact with matter produce neutrinos. We search neutrino emission using machine learning techniques applied ten years data IceCube Neutrino Observatory. identify Galactic plane 4.5$σ$ level...
Abstract We present a measurement of the high-energy astrophysical muon–neutrino flux with IceCube Neutrino Observatory. The uses high-purity selection 650k neutrino-induced muon tracks from northern celestial hemisphere, corresponding to 9.5 yr experimental data. With respect previous publications, is improved by increased size event sample and extended model testing beyond simple power-law hypotheses. An updated treatment systematic uncertainties atmospheric background fluxes has been...
Gamma-ray bursts (GRBs) have long been considered a possible source of high-energy neutrinos. While no correlations yet detected between neutrinos and GRBs, the recent observation GRB 221009A - brightest observed by Fermi-GBM to date first one be above an energy 10 TeV provides unique opportunity test for hadronic emission. In this paper, we leverage wide range IceCube Neutrino Observatory search from 221009A. We find significant deviation background expectation across event samples ranging...
Abstract The combined fit of the measured energy spectrum and shower maximum depth distributions ultra-high-energy cosmic rays is known to constrain parameters astrophysical models with homogeneous source distributions. Studies distribution cosmic-ray arrival directions show a better agreement in which fraction flux non-isotropic associated nearby radio galaxy Centaurus A or catalogs such as that starburst galaxies. Here, we present novel combination both analyses by simultaneous directions,...
Abstract Active galactic nuclei (AGN) are promising candidate sources of high-energy astrophysical neutrinos, since they provide environments rich in matter and photon targets where cosmic-ray interactions may lead to the production gamma rays neutrinos. We searched for neutrino emission from AGN using Swift-BAT Spectroscopic Survey catalog hard X-ray 12 yr IceCube muon track data. First, upon performing a stacked search, no significant was found. Second, we neutrinos list 43 found an excess...
High-statistics cross sections for the reactions gamma + p --> K^+ Lambda and Sigma^0 have been measured using CLAS at Jefferson Lab center-of-mass energies W between 1.6 2.53 GeV, -0.85 < cos theta_{K^+}^{c.m.}< +0.95. In channel we confirm a resonance-like structure near W=1.9 GeV backward kaon angles. The position width of this change with angle, indicating that more than one resonance is likely playing role. forward angles all well described by t-channel scaling characteristic Regge...
We report the first results of beam-spin asymmetry measured in reaction $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}\mathrm{ep}\ensuremath{\gamma}$ at a beam energy 4.25 GeV. A large with $\mathrm{sin}\ensuremath{\varphi}$ modulation is observed, as predicted for interference term deeply virtual compton scattering (DVCS) and Bethe-Heitler process. The amplitude this...
Models of baryon structure predict a small quadrupole deformation the nucleon due to residual tensor forces between quarks or distortions from pion cloud. Sensitivity quark versus degrees freedom occurs through Q2 dependence magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in gamma*p-->Delta(+)-->p pi(0) transition. We report new experimental values for ratios E(1+)/M(1+) S(1+)/M(1+) over range = 0.4-1.8 GeV2, extracted precision p(e,e(')p)pi(0) data using truncated multipole...