arXiv subjects

K. Peters

Publications and source records attributed to K. Peters.

At least 19 recordsLinked to original sources

arXiv2026

Detection of high-frequency gravitational waves using SRF cavities

Today, apart from some isolated R&D efforts, there are no gravitational wave (GW) experiments, yet which explore a large part of the vast frequency range above the LIGO/Virgo band. It is planned to establish an experiment at Deutsches Elektronen-Synchrotron (DESY) and at the Superconducting Quantum Materials and Systems (SQMS) Center at Fermi National Accelerator Laboratory (Fermilab) to search for high-frequency GWs in the frequency range of 10 kHz to 100 MHz. The basic idea is to use superconducting radiofrequency (SRF) cavities to detect tiny harmonic deformations induced by GWs which change the boundary conditions of the oscillating electromagnetic field. This paper summarizes the challenging environmental boundary requirements, and the R&D to operate a cavity using a low level RF (LLRF) system which pushes beyond state-of-the-art accuracy and resolutions and a seismic noise mitigated cryostat at 1.8 K. The focus of this paper is the warm and cold commissioning of a prototype cavity, built 20 years ago during the MAGO collaboration, and its first measurement in our collaborative research project.

physics.acc-ph↗

arXiv2025

The PANDA Barrel DIRC: From design to assembly

The Barrel DIRC counter will serve as the primary particle identification detector in the PANDA experiment, enabling high-precision hadron physics studies through antiproton-proton annihilations across a momentum range of 1.5 GeV/c to 15 GeV/c. It is designed to distinguish charged pions from kaons with a separation of at least 3 standard deviations up to 3.5 GeV/c within polar angles of 22 degrees to 140 degrees. A lens focusing is used the first time in a DIRC detector. After a successful evaluation in particle beams, the key components, i.e. radiator bars and photon sensors, were purchased and tested.

physics.ins-det↗

arXiv2024

First Measurement of Near- and Sub-Threshold $J/\psi$ Photoproduction off Nuclei

We report on the first measurement of $J/\psi$ photoproduction from nuclei in the photon energy range of $7$ to $10.8$ GeV, extending above and below the photoproduction threshold in the free proton of $\sim8.2$ GeV. The experiment used a tagged photon beam incident on deuterium, helium, and carbon, and the GlueX detector at Jefferson Lab to measure the semi-inclusive $A(\gamma,e^+e^-p)$ reaction with a dilepton invariant mass $M(e^+e^-)\sim m_{J/\psi}=3.1$ GeV. The incoherent $J/\psi$ photoproduction cross sections in the measured nuclei are extracted as a function of the incident photon energy, momentum transfer, and proton reconstructed missing light-cone momentum fraction. Comparisons with theoretical predictions assuming a dipole form factor allow extracting a gluonic radius for bound protons of $\sqrt{\langle r^2\rangle}=0.85\pm0.14$ fm. The data also suggest an excess of the measured cross section for sub-threshold production and for interactions with high missing light-cone momentum fraction protons. The measured enhancement can be explained by modified gluon structure for high-virtuality bound-protons.

nucl-ex↗

arXiv2024

The PANDA Barrel DIRC

The PANDA experiment at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR), Darmstadt, Germany, will address fundamental questions of hadron physics using $\bar{p}p$ annihilations. Excellent Particle Identification (PID) over a large range of solid angles and particle momenta will be essential to meet the objectives of the rich physics program. Charged PID in the target region will be provided by a Barrel DIRC (Detection of Internally Reflected Cherenkov light) counter. The Barrel DIRC, covering the polar angle range of 22-140 degrees, will provide a $\pi/K$ separation power of at least 3 standard deviations for charged particle momenta up to 3.5 GeV/c. The design of the Barrel DIRC features narrow radiator bars made from synthetic fused silica, an innovative multi-layer spherical lens focusing system, a prism-shaped synthetic fused silica expansion volume, and an array of lifetime-enhanced Microchannel Plate PMTs (MCP-PMTs) to detect the hit location and arrival time of the Cherenkov photons. Detailed Monte-Carlo simulations were performed, and reconstruction methods were developed to study the performance of the system. All critical aspects of the design and the performance were validated with system prototypes in a mixed hadron beam at the CERN PS. In 2020 the PANDA Barrel DIRC project advanced from the design stage to component fabrication. The series production of the fused silica bars was successfully completed in 2021 and delivery of the MCP-PMTs started in May 2022.

hep-ex↗

arXiv2023

Lifetime and performance of the very latest microchannel-plate photomultipliers

The PANDA experiment at the FAIR facility at GSI will study hadron physics using a high intensity antiproton beam of up to 15 GeV/c momentum to perform high precision spectroscopy. Two DIRC detectors with their image planes residing in an $\sim$1 T magnetic field will be used in the experiment. The only suitable photon detectors for both DIRCs were identified to be Microchannel-Plate Photomultipliers (MCP-PMTs). Since the aging problems of MCP-PMTs were solved recently by coating the MCPs with the so-called ALD-technique (atomic layer deposition) we are investigating devices which are significantly improved with respect to other parameters, as, e.g., the collection efficiency (CE) and the quantum efficiency (QE). The latest generation of MCP-PMTs can reach a detective quantum efficiency DQE = QE - CE of 30%. This paper will present the performance of the most advanced 53 $\times$ 53 mm$^2$ ALD-coated MCP-PMTs from Photonis (8 $\times$ 8 and 3 $\times$ 100 anodes) and Photek (8 $\times$ 8 anodes), also inside the magnetic field. With a picosecond laser and a multi-hit capable DAQ system which allows read out up to 300 pixels simultaneously, parameters like darkcount rate, afterpulse probability and time resolution can be investigated as a function of incident photon position.

physics.ins-det↗

arXiv2023

Performance of the most recent Microchannel-Plate PMTs for the PANDA DIRC detectors at FAIR

In the PANDA experiment at the FAIR facility at GSI two DIRC (Detection of Internally Reflected Cherenkov light) detectors will be used for $\pi$/K separation up to 4 GeV/c. Due to their location in a high magnetic field and other stringent requirements like high detection efficiency, low dark count rate, radiation hardness, long lifetime and good timing, MCP-PMTs (microchannel-plate photomultiplier) were the best choice of photon sensors for the DIRC detectors in the PANDA experiment. This paper will present the performance of some of the latest 2$\times$2 inch$^2$ MCP-PMTs from Photek and Photonis, including the first mass production tubes for the PANDA Barrel DIRC from Photonis. Performance parameters like the collection efficiency (CE), quantum efficiency (QE), and gain homogeneity were determined. The effect of magnetic fields on some properties like gain and charge cloud width was investigated as well. Apart from that the spatial distribution of many internal parameters like time resolution, dark count rate, afterpulse ratio, charge sharing crosstalk and recoil electrons were measured simultaneously with a multihit capable DAQ system. The latest generation of Photonis MCP-PMTs shows an unexpected "escalation" effect where the MCP-PMT itself produces photons.

physics.ins-det↗

arXiv2022

Deep Machine Learning for the PANDA Software Trigger

Deep machine learning methods have been studied for the software trigger of the future PANDA experiment at FAIR, using Monte Carlo simulated data from the GEANT-based detector simulation framework PandaRoot. Ten physics channels that cover the main physics topics, including electromagnetic, exotic, charmonium, open charm, and baryonic reaction channels, have been investigated at four different anti-proton beam momenta. Binary and multi-class classification together with seven different network architectures have been studied. Finally a residual convolutional neural network with four residual blocks in a binary classification scheme has been chosen due to its extendability, performance and stability. The presented study represents a feasibility study of a completely software-based trigger system. Compared to a conventional selection method, the deep machine learning approach achieved a significant efficiency gain of up to 200\%, while keeping the background reduction factor at the required level of 1/1000. Furthermore, it is shown that the use of additional input variables can improve the data quality for subsequent analysis. This study shows that the PANDA software trigger can benefit greatly from the deep machine learning methods.

physics.ins-det↗

arXiv2022

CORE -- a COmpact detectoR for the EIC

The COmpact detectoR for the Eic (CORE) Proposal was submitted to the EIC "Call for Collaboration Proposals for Detectors". CORE comprehensively covers the physics scope of the EIC Community White Paper and the National Academies of Science 2018 report. The design exploits advances in detector precision and granularity to minimize size. The central detector includes a 3Tesla, 2.5m solenoid. Tracking is primarily silicon. Electromagnetic calorimetry is based on the high performance crystals. Ring-imaging Cherenkov detectors provide hadronic particle identification.

physics.ins-det↗

arXiv2021

The PANDA DIRCs

The PANDA experiment at the FAIR facility adresses open questions in hadron physics with antiproton beams in the momentum range of 1.5-15 GeV/c. The antiprotons are stored and cooled in a High Energy Storage RING (HESR) with a momentum spread down to Dp/p = 4*10^-5. A high luminosity of up to 2*10^32 cm-2 s-1 can be achieved. An excellent hadronic particle identification (PID) will be provided by two Cherenkov detectors using the priciple of Detection of Internally Reflected Cherenkov light (DIRC). In the forward direction from polar angles of 5 degree to 22 degree, the Endcap Disc DIRC (EDD) separates pions from kaons up to momenta of 4 GeV/c. Between 22 degree and 140 degree the Barrel DIRC cleanly separates pions from kaons for momenta up to 3.5 GeV/c. This article describes the design of the Barrel DIRC and of the Endcap Disc DIRC and the validation of their designs in particle beams at the CERN PS.

physics.ins-det↗

arXiv2020

Time imaging reconstruction for the PANDA Barrel DIRC

The innovative Barrel DIRC (Detection of Internally Reflected Cherenkov light) counter will provide hadronic particle identification (PID) in the central region of the PANDA experiment at the new Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany. This detector is designed to separate charged pions and kaons with at least 3 standard deviations for momenta up to 3.5 GeV/c, covering the polar angle range of 22$^{\circ}$-140$^{\circ}$. An array of microchannel plate photomultiplier tubes is used to detect the location and arrival time of the Cherenkov photons with a position resolution of 2 mm and time precision of about 100 ps. The time imaging reconstruction has been developed to make optimum use of the observables and to determine the performance of the detector. This reconstruction algorithm performs particle identification by directly calculating the maximum likelihoods using probability density functions based on detected photon propagation time in each pixel, determined directly from the data, or analytically, or from detailed simulations.

physics.ins-det↗

arXiv2020

Status of the PANDA Barrel DIRC

The PANDA experiment will use cooled antiproton beams with high intensity stored1 in the High Energy Storage Ring at FAIR. Reactions on a fixed target producing charmed hadrons will shed light on the strong QCD. Three ring imaging Cherenkov counters are used for charged particle identification. The status of the Barrel DIRC (Detection of Internally Reflected Cherenkov light) is described. Its design is robust and its performance validated in experiments with test beams. The PANDA Barrel DIRC has entered the construction phase and will be installed in 2023/2024.

physics.ins-det↗

arXiv2019

Particle Identification with DIRCs at PANDA

The DIRC technology (Detection of Internally Reflected Cherenkov light) offers an excellent possibility to minimize the form factor of Cherenkov detectors in hermetic high energy detectors. The PANDA experiment at FAIR in Germany will combine a barrel-shaped DIRC with a disc-shaped DIRC to cover an angular range of 5 to 140 degrees. Particle identification for pions and kaons with a separation power of 3 standard deviations or more will be provided for momenta between 0.5 GeV/c and 3.5 GeV/c in the barrel region and up to 4 GeV/c in the forward region. Even though the concept is simple, the design and construction of a DIRC is challenging. High precision optics and mechanics are required to maintain the angular information of the Cherenkov photons during multiple internal reflections and to focus the individual photons onto position sensitive photon detectors. These sensors must combine high efficiencies for single photons with low dark count rates and good timing resolution at high rates. The choice of radiation hard fused silica for the optical material and of MCP-PMT photon sensors is essential for DIRC detectors to survive in an environment of radiation and strong magnetic field. The two DIRC detectors differ in the focusing optics, in the treatment of chromatic dispersion and in the electronic readout systems. The technical design of the two DIRC detectors and their validation by testing prototypes in a mixed particle beam at CERN are presented.

physics.ins-det↗

arXiv2019

The Innovative Design of the Endcap Disc DIRC Detector for PANDA at FAIR

The key component of the future PANDA experiment at FAIR is a fixed-target detector for collisions of antiprotons with a proton target up to a beam momentum of 15 GeV/c and is designed to address a large number of open questions in the hadron physics sector. In order to guarantee an excellent PID for charged hadrons in the polar angle range between $5^\circ$ and $22^\circ$, a new type of Cherenkov detector called Endcap Disc DIRC (EDD) has been developed for the forward endcap of the PANDA target spectrometer. The desired separation power of at least 3 s.d. for the separation of $\pi^\pm$ and $K^\pm$ up to particle momenta of 4 GeV/c was determined with simulation studies and validated during various testbeam campaigns at CERN and DESY.

physics.ins-det↗

arXiv2019

Coupled Channel Analysis of $\bar{p} p \rightarrow \pi^0 \pi^0 \eta$, $\pi^0 \eta \eta$ and $K^+ K^- \pi^0$ at 900 $MeV/c$ and of $\pi\pi$-Scattering Data

A partial wave analysis of antiproton-proton annihilation data in flight at 900 $MeV/c$ into $\pi^0 \pi^0 \eta$ , $\pi^0 \eta \eta$ and $K^+ K^- \pi^0$ is presented. The data were taken at LEAR by the Crystal Barrel experiment in 1996. The three channels have been coupled together with $\pi\pi$-scattering isospin I=0 S- and D-wave as well as I=1 P-wave data utilizing the K-matrix approach. Analyticity is treated using Chew-Mandelstam functions. In the fit all ingredients of the K-matrix, including resonance masses and widths, were treated as free parameters. In spite of the large number of parameters, the fit results are in the ballpark of the values published by the Particle Data Group. In the channel $\pi^0 \pi^0 \eta$ a significant contribution of the spin exotic $I^G=1^-$ $J^{PC}=1^{-+}$ $\pi_1$-wave with a coupling to $\pi^0 \eta$ is observed. Furthermore the contributions of $\phi(1020) \pi^0$ and $K^*(892)^\pm K^\mp$ in the channel $K^+ K^- \pi^0$ have been studied in detail. The differential production cross section for the two reactions and the spin-density-matrix elements for the $\phi(1020)$ and $K^*(892)^\pm$ have been extracted. No spin-alignment is observed for both vector mesons. The spin density matrix elements have been also determined for the spin exotic wave.

hep-ex↗

arXiv2019

The Innovative Design of the PANDA Barrel DIRC

The Barrel DIRC of the PANDA experiment at FAIR will cleanly separate pions from kaons for the physics program of PANDA. Innovative solutions for key components of the detector sitting in the strong magnetic field of the compact PANDA target spectrometer as well as two reconstruction methods were developed in an extensive prototype program. The technical design and present results from the test beam campaigns at the CERN PS in 2017 and 2018 are discussed.

physics.ins-det↗

arXiv2019

The Barrel DIRC detector of PANDA

The PANDA experiment is one of the four large experiments being built at FAIR in Darmstadt. It will use a cooled antiproton beam on a fixed target within the momentum range of 1.5 to 15 GeV/c to address questions of strong QCD, where the coupling constant $\alpha_s \gtrsim 0.3$. The luminosity of up to $2 \cdot 10^{32} cm^{-2}s^{-1}$ and the momentum resolution of the antiproton beam down to \mbox{$\Delta$p/p = 4$\cdot10^{-5}$} allows for high precision spectroscopy, especially for rare reaction processes. Above the production threshold for open charm mesons the production of kaons plays an important role for identifying the reaction. The DIRC principle allows for a compact particle identification for charged particles in a hermetic detector, limited in size by the electromagnetic lead tungstate calorimeter. The Barrel DIRC in the target spectrometer covers polar angles between $22^\circ$ and $140^\circ$ and will achieve a pion-kaon separation of 3 standard deviations up to 3.5 GeV/$c$. Here, results of a test beam are shown for a single radiator bar coupled to a prism with $33^\circ$ opening angle, both made from synthetic fused silica read out with a photon detector array with 768 pixels.

physics.ins-det↗

arXiv2017

The PANDA DIRC Detectors at FAIR

The PANDA detector at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR) addresses fundamental questions of hadron physics. An excellent hadronic particle identification (PID) will be accomplished by two DIRC (Detection of Internally Reflected Cherenkov light) counters in the target spectrometer. The design for the barrel region covering polar angles between 22 deg. to 140 deg. is based on the successful BABAR DIRC with several key improvements, such as fast photon timing and a compact imaging region. The novel Endcap Disc DIRC will cover the smaller forward angles between 5 deg. (10 deg.) to 22 deg. in the vertical (horizontal) direction. Both DIRC counters will use lifetime-enhanced microchannel plate PMTs for photon detection in combination with fast readout electronics. Geant4 simulations and tests with several prototypes at various beam facilities have been used to evaluate the designs and validate the expected PID performance of both PANDA DIRC counters.

physics.ins-det↗

arXiv2015

Issues and Opportunities in Exotic Hadrons

The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons. Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks, pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and theoretical issues concerning heavy exotic hadrons is presented.

hep-ph↗