N. Zachariou
A5009397487- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Advanced NMR Techniques and Applications
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- High-pressure geophysics and materials
- Radiation Detection and Scintillator Technologies
- Pulsars and Gravitational Waves Research
- Neutrino Physics Research
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Medical Imaging Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Electron and X-Ray Spectroscopy Techniques
- Scientific Research and Discoveries
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Inorganic Fluorides and Related Compounds
- Astronomical and nuclear sciences
- Astrophysics and Cosmic Phenomena
- Photoreceptor and optogenetics research
University of York
2019-2025
Thomas Jefferson National Accelerator Facility
2017-2024
Florida International University
2022-2023
George Washington University
2011-2023
Argonne National Laboratory
2015-2023
Campbell Collaboration
2012-2023
Istituto Nazionale di Fisica Nucleare, Sezione di Genova
2018-2023
Istituto Nazionale di Fisica Nucleare, Sezione di Catania
2023
Duquesne University
2022-2023
Johannes Gutenberg University Mainz
2020-2023
Constraints on the quantum decoherence of entangled <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>γ</a:mi></a:math> quanta at mega-electron-volt scale, such as those produced following positron annihilation, have remained elusive for many decades. We present first statistically and kinematically precise experimental data triple Compton scattering <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>γ</c:mi></c:math>. An entanglement...
Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this true, then hyperon-nucleon interactions will play a significant part star equation state (EOS). Yet, compared other elastic scattering processes, there very little data $\Lambda$-$N$ scattering. This experiment utilized CLAS detector study $\Lambda p \rightarrow \Lambda p$ cross section incident $\Lambda$ momentum range 0.9-2.0 GeV/c. first reaction several decades. The new sections have...
The Electron-Ion Collider (EIC), a state-of-the-art facility for studying the strong force, is expected to begin commissioning its first experiments in 2028. This an opportune time artificial intelligence (AI) be included from start at this and all phases that lead up experiments. second annual workshop organized by AI4EIC working group, which recently took place, centered on exploring current prospective application areas of AI EIC. not only beneficial EIC, but also provides valuable...
A precise measurement of the differential cross sections dσ/dΩ and linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on proton below pion threshold has been performed with a tagged almost 4π detector at Mainz Microtron. The incident photons were produced by recently upgraded Glasgow-Mainz tagging facility impinged cryogenic liquid hydrogen target, scattered detected in Crystal Ball/TAPS setup. Using highest statistics data ever measured along two effective field theories...
We report the first measurement of differential and total cross sections for $\ensuremath{\gamma}d\ensuremath{\rightarrow}{K}^{0}\mathrm{\ensuremath{\Lambda}}(p)$ reaction, using data from CLAS detector at Thomas Jefferson National Accelerator Facility. Data collected during two separate experimental runs were studied with photon-energy coverage 0.8--3.6 GeV 0.5-- 2.6 GeV, respectively. The measurements are consistent giving confidence in method determination systematic uncertainties....
The $\ensuremath{\gamma}n\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}n$ differential cross section evaluated for 27 energy bins span the photon-energy range 290--813 MeV ($W=1.195$--1.553 GeV) and pion c.m. polar production angles, ranging from ${18}^{\ensuremath{\circ}}$ to ${162}^{\ensuremath{\circ}}$, making use of model-dependent nuclear corrections extract ${\ensuremath{\pi}}^{0}$ data on neutron measurements deuteron target. Additionally, total photoabsorption was measured. tagged...
Abstract Positron Emission Tomography (PET) is a widely-used imaging modality for medical research and clinical diagnosis. Imaging of the radiotracer obtained from detected hit positions two positron annihilation photons in detector array. The image degraded by backgrounds random coincidences in-patient scatter events which require correction. In addition to geometric information, are predicted be produced quantum-entangled state, resulting enhanced correlations between their subsequent...
We report a new measurement of the beam-spin asymmetry $\boldsymbol{\Sigma}$ for $\vec{\gamma} n \rightarrow K^+\Sigma^-$ reaction using quasi-free neutrons in liquid-deuterium target. The dataset includes data at previously unmeasured photon energy and angular ranges, thereby providing constraints on partial wave analyses used to extract properties excited nucleon states. experimental were obtained CEBAF Large Acceptance Spectrometer (CLAS), housed Hall B Thomas Jefferson National...
We report a measurement of the spin polarisation recoiling neutron in deuterium photodisintegration, utilising new large acceptance polarimeter within Crystal Ball at MAMI. The measured photon energy range 300~--~700~MeV provides first recoil energies where quark substructure deuteron plays role, thereby providing important constraints on photodisintegration mechanisms. A very high narrow structure centred around $E_{\gamma}\sim$~570~MeV is observed, which inconsistent with current...
The transition from the nucleon to $\mathrm{\ensuremath{\Delta}}(1232)$ resonance is a sensitive test for models of structure. A magnetic dipole ($M1$) quark spin-flip essentially dominates photoexcitation $\mathrm{\ensuremath{\Delta}}$, but smaller components in and $\mathrm{\ensuremath{\Delta}}$ wave functions allow also electric quadrupole ($E2$) contributions. ratio $E2/M1$ then provides fundamental information on both spatial deformation or corresponding $D$ states their quark-model...
We report a measurement of beam–target double-polarisation observable (E) for the γ→n→(p)→K+Σ−(p) reaction. The data were obtained impinging circularly-polarised energy-tagged photon beam Hall B at Jefferson Lab on longitudinally-polarised frozen-spin hydrogen deuteride (HD) nuclear target. E an effective neutron target was determined centre-of-mass energies 1.70≤W≤2.30 GeV, with reaction products detected over wide angular acceptance by CLAS spectrometer. These new give unique constraints...
We report measurements of π+ and π0 meson photoproduction from longitudinally spin-polarised protons by an energy tagged (0.73-2.3 GeV) linearly polarised photon beam. A close to complete solid angle coverage for the reaction products was provided CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The double-polarisation observable G is extracted Maximum Likelihood fits data, enabling first accurate determination γ→p→→π+n, while also significantly extending kinematic γ→p→→π0p. This...
We utilise an isobar model to investigate the $K^+ \Sigma^-$ photoproduction off a neutron in resonance region. Except for Born terms, we include high-spin (spin-3/2 and spin-5/2) nucleon resonances consistent formalism together with few $\Delta$ kaon achieve acceptable agreement data. Interestingly, reveal that no hyperon are needed reasonable description of On other hand $N(1720)3/2^+$ was found be very important correct The free parameters were fitted experimental data from LEPS CLAS...
The Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) is a research centre dedicated to providing high energy particle beams and peak brightness radiation pulses users across all scientific engineering disciplines. A pair Ti:Sapphire femtosecond laser systems (40 TW power at 10 Hz pulse repetition rate 350 5 Hz, respectively) are drivers suite laser-plasma accelerator beamlines housed series shielded areas. petawatt-scale delivers 45 W average that establishes it as...
The beam-spin asymmetry, $\Sigma$, for the reaction $\gamma d\rightarrow pn$ has been measured using CEBAF Large Acceptance Spectrometer (CLAS) at Thomas Jefferson National Accelerator Facility (JLab) six photon-energy bins between 1.1 and 2.3 GeV, proton angles in center-of-mass frame, $\theta_{c.m.}$, $25^\circ$ $160^\circ$. These are first measurements of asymmetries $\theta_{c.m.}=90^\circ$ photon-beam energies above 1.6 other than $\theta_{c.m.}=90^\circ$. angular energy dependence...
Photoproduction of π0π±-pairs from quasifree nucleons bound in the deuteron has been investigated to study helicity dependence this reaction. Measurements with a liquid deuterium target were used extract unpolarized cross sections for reactions on protons and neutrons. A deuterated, longitudinally polarized solid-butanol target, together circularly photon beam, determined double polarization observable E. From these results spin-dependent σ1/2 σ3/2, corresponding anti-parallel parallel spin...
We report the measurement of helicity asymmetry <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>E</a:mi></a:math> for <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>p</c:mi><c:msup><c:mi>π</c:mi><c:mn>0</c:mn></c:msup></c:math> and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>n</e:mi><e:msup><e:mi>π</e:mi><e:mo>+</e:mo></e:msup></e:math> final states using, first time, an elliptically polarized photon...
The CLAS Collaboration provides a comment on the physics interpretation of results presented in paper published by M. Amaryan et al. regarding possible observation narrow structure mass spectrum photoproduction experiment.
In Ref. [1], the authors claim to observe a narrow structure in mass spectrum constructed from (pK_L) system using data CLAS detector. The interpretation of this structure given in [1] is as follows: “It may be due photoproduction Theta+ pentaquark or some unknown Sigma∗ resonance.” go on say that “it unlikely for observed This analysis was reviewed by Collaboration, following established procedures all papers, and did not receive approval. purpose Comment explain reasons why approved...
We report the measurement of helicity asymmetry $E$ for $p\pi^0$ and $n\pi^+$ final states using, first time, an elliptically polarized photon beam in combination with a longitudinally target at Crystal Ball experiment MAMI. The results agree very well data that were taken circularly beam, showing it is possible to simultaneously measure polarization observables require linearly (e.g.~$G$) photons (e.g.~$E$) target. new cover energy range 270 - 1400 MeV state (230 842 state) full pion polar...
Elucidating the role of strange baryons (hyperons) in neutron stars requires detailed knowledge hyperon–nucleon interactions light (u,d,s) quark sector. The structure hyperons and their excitation spectra also directly impact, are an input to, models big-bang nucleosynthesis. upcoming K-long Facility will provide a much-needed intense clean neutral meson beam, from which can be produced at rates where hyperon structure, higher-order studied with new level accuracy for hitherto unreachable...