A. Caldwell
A5061406434- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Bayesian Methods and Mixture Models
- Muon and positron interactions and applications
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Statistical Methods and Bayesian Inference
- Statistical Methods and Inference
- Laser-Matter Interactions and Applications
- Solar and Space Plasma Dynamics
- Gaussian Processes and Bayesian Inference
- Atomic and Subatomic Physics Research
- Bayesian Modeling and Causal Inference
- Markov Chains and Monte Carlo Methods
- Radiation Therapy and Dosimetry
- Nuclear Physics and Applications
Max Planck Institute for Physics
2015-2024
Campbell Collaboration
2020-2022
Max Planck Society
2006-2019
Google (United States)
2019
University College London
2016-2017
University of Birmingham
2017
Ludwig-Maximilians-Universität München
2015
Max Planck Innovation
2005-2012
University of California, Los Angeles
2010
Budker Institute of Nuclear Physics
2010
A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral charged current $$e^{\pm }p$$ scattering zero beam polarisation. The data were taken proton energies 920, 820, 575 460 GeV an electron energy 27.5 GeV. correspond to integrated luminosity about 1 fb $$^{-1}$$ span six orders magnitude in negative four-momentum-transfer squared, $$Q^2$$ , Bjorken x. correlations systematic uncertainties evaluated...
A combination is presented of the inclusive deep inelastic cross sections measured by H1 and ZEUS Collaborations in neutral charged current unpolarised ep scattering at HERA during period 1994-2000. The data span six orders magnitude negative four-momentum-transfer squared, Q^2, Bjorken x. method used takes correlations systematic uncertainties into account, resulting an improved accuracy. combined are sole input a NLO QCD analysis which determines new set parton distributions, HERAPDF1.0,...
We propose a new strategy to search for dark matter axions in the mass range of $40--400\text{ }\ensuremath{\mu}\mathrm{eV}$ by introducing dielectric haloscopes, which consist disks placed magnetic field. The changing media cause discontinuities axion-induced electric field, leading generation propagating electromagnetic waves satisfy continuity requirements at interfaces. Large-area with adjustable distances boost microwave signal (10--100 GHz) an observable level and allow one scan over...
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
A fully compensating uranium—scintillator calorimeter was constructed for the ZEUS detector at HERA. Several of barrel modules were subjected to beam tests Fermilab before shipping them DESY installation. The calibrations used beams electrons and hadrons, measuring uniformity response, checking resolution. runs also provided opportunity test a large fraction actual readout system in an integrated environment more than one year HERA turn on. experiment utilized two computer controlled...
The design of the readout system for high resolution ZEUS calorimeter is described. employs 10 MHz switched capacitor pipelines and digital signal processors, provides linear operation over a 17-bit dynamic range. implementation also discussed.
Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced $\sigma_{\rm red}^{c\bar{c}}$ for obtained kinematic range photon virtuality 2.5≤Q 2≤2000 GeV2 Bjorken scaling variable 3⋅10−5≤x≤5⋅10−2. The combination method accounts correlations systematic uncertainties among different data sets. combined together with inclusive used as input a detailed NLO QCD analysis to study influence heavy flavour...
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment CERN the world׳s first experiment. AWAKE will be installed in former CNGS facility uses 400 GeV/c beam bunches from SPS. experiments focus on self-modulation instability of long (rms ~12 cm) bunch plasma. These are planned for end 2016. Later, 2017/2018, low energy (~15 MeV)...
Next-to-leading-order QCD analyses of the ZEUS data on deep inelastic scattering together with fixed-target have been performed, from which gluon and quark densities proton value strong coupling constant αs(MZ) were extracted. The study includes a full treatment experimental systematic uncertainties including point-to-point correlations. resulting in parton density functions are presented. A combined fit for yields agreement world average. derived alone indicate importance HERA determining...
A small electromagnetic sampling calorimeter, installed in the ZEUS experiment 1995, significantly enhanced acceptance for very low x and Q^2 inelastic neutral current scattering, e^{+}p \to e^{+}X, at HERA. measurement of proton structure function F_2 total virtual photon-proton (\gamma^*p) cross-section is presented 0.11 \le Q^{2} 0.65 GeV^2 2 \times 10^{-6} 6 10^{-5}, corresponding to a range \gamma^{*}p c.m. energy 100 W 230 GeV. Comparisons with various models are also presented.
New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach to exploit properties plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or electron bunch into plasma. However, maximum energy gain electrons accelerated in a single stage limited driver. Proton bunches are most drivers wakefields accelerate TeV scale stage. An experimental program at CERN—the...
Measurements of open charm and beauty production cross sections in deep inelastic ep scattering at HERA from the H1 ZEUS Collaborations are combined. Reduced obtained kinematic range negative four-momentum transfer squared photon $$2.5~\hbox {GeV}^2\le Q^2 \le 2000\, \hbox {GeV}^2$$ Bjorken scaling variable $$3 \cdot 10^{-5} x_\mathrm{Bj} 5 10^{-2}$$ . The combination method accounts for correlations statistical systematic uncertainties among different datasets. Perturbative QCD calculations...
We give direct experimental evidence for the observation of full transverse self-modulation a long, relativistic proton bunch propagating through dense plasma. The exits plasma with periodic density modulation resulting from radial wakefield effects. show that is seeded by ionization front created using an intense laser pulse copropagating bunch. extends over length following seed point. By varying one order magnitude, we frequency scales expected dependence on density, i.e., it equal to...
The seeded self-modulation of a relativistic, charged particle bunch in plasma is shown to grow both along the and plasma, resulting transverse wakefield amplitudes that far exceed initial seed values.
We show in experiments that a long, underdense, relativistic proton bunch propagating plasma undergoes the oblique instability, which we observe as filamentation. determine threshold value for ratio between transverse size and skin depth instability to occur. At threshold, outcome of experiment alternates filamentation self-modulation (evidenced by longitudinal modulation into microbunches). Time-resolved images density distribution reveal grows an observable level late along bunch,...