Author: Matteo Bonanomi
Publisher: Springer Nature
ISBN: 3031268334
Category : Science
Languages : en
Pages : 281
Book Description
This book highlights the most complete characterization of the Higgs boson properties performed to date in the "golden channel," i.e., decay into a pair of Z bosons which subsequently decay into four leptons. The data collected by the CMS experiment in the so-called Run-II data-taking period of the LHC are used to produce an extensive set of results that test in detail the predictions of the Standard Model. Given the remarkable predictive power of the SM when including the Higgs boson, possible new physics will require even more extensive studies at higher statistics. A massive upgrade of the detectors is necessary to maintain the current physics performance in the harsh environment of the High-Luminosity LHC (HL-LHC) project, expected to start by the end of 2027. The CMS Collaboration will replace the current endcap calorimeters with a High Granularity Calorimeter (HGCAL). The HGCAL will be the very first large-scale silicon-based imaging calorimeter ever employed in a high-energy physics experiment. This book presents the results of the analysis of the test beam data collected with the first large-scale prototype of the HGCAL. The results of this analysis are used to corroborate the final design of the HGCAL and its nominal physics performance expected for the HL-LHC operations.
Response of the High Granularity Calorimeter HGCAL and Characterisation of the Higgs Boson
Author: Matteo Bonanomi
Publisher: Springer Nature
ISBN: 3031268334
Category : Science
Languages : en
Pages : 281
Book Description
This book highlights the most complete characterization of the Higgs boson properties performed to date in the "golden channel," i.e., decay into a pair of Z bosons which subsequently decay into four leptons. The data collected by the CMS experiment in the so-called Run-II data-taking period of the LHC are used to produce an extensive set of results that test in detail the predictions of the Standard Model. Given the remarkable predictive power of the SM when including the Higgs boson, possible new physics will require even more extensive studies at higher statistics. A massive upgrade of the detectors is necessary to maintain the current physics performance in the harsh environment of the High-Luminosity LHC (HL-LHC) project, expected to start by the end of 2027. The CMS Collaboration will replace the current endcap calorimeters with a High Granularity Calorimeter (HGCAL). The HGCAL will be the very first large-scale silicon-based imaging calorimeter ever employed in a high-energy physics experiment. This book presents the results of the analysis of the test beam data collected with the first large-scale prototype of the HGCAL. The results of this analysis are used to corroborate the final design of the HGCAL and its nominal physics performance expected for the HL-LHC operations.
Publisher: Springer Nature
ISBN: 3031268334
Category : Science
Languages : en
Pages : 281
Book Description
This book highlights the most complete characterization of the Higgs boson properties performed to date in the "golden channel," i.e., decay into a pair of Z bosons which subsequently decay into four leptons. The data collected by the CMS experiment in the so-called Run-II data-taking period of the LHC are used to produce an extensive set of results that test in detail the predictions of the Standard Model. Given the remarkable predictive power of the SM when including the Higgs boson, possible new physics will require even more extensive studies at higher statistics. A massive upgrade of the detectors is necessary to maintain the current physics performance in the harsh environment of the High-Luminosity LHC (HL-LHC) project, expected to start by the end of 2027. The CMS Collaboration will replace the current endcap calorimeters with a High Granularity Calorimeter (HGCAL). The HGCAL will be the very first large-scale silicon-based imaging calorimeter ever employed in a high-energy physics experiment. This book presents the results of the analysis of the test beam data collected with the first large-scale prototype of the HGCAL. The results of this analysis are used to corroborate the final design of the HGCAL and its nominal physics performance expected for the HL-LHC operations.
Particle Physics Reference Library
Author: Christian W. Fabjan
Publisher: Springer Nature
ISBN: 3030353184
Category : Heavy ions
Languages : en
Pages : 1083
Book Description
This second open access volume of the handbook series deals with detectors, large experimental facilities and data handling, both for accelerator and non-accelerator based experiments. It also covers applications in medicine and life sciences. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access
Publisher: Springer Nature
ISBN: 3030353184
Category : Heavy ions
Languages : en
Pages : 1083
Book Description
This second open access volume of the handbook series deals with detectors, large experimental facilities and data handling, both for accelerator and non-accelerator based experiments. It also covers applications in medicine and life sciences. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access
Beam Test Calorimeter Prototypes for the CMS Calorimeter Endcap Upgrade
Author: Thorben Quast
Publisher: Springer Nature
ISBN: 3030902021
Category : Science
Languages : en
Pages : 290
Book Description
In order to cope with the increased radiation level and the challenging pile-up conditions at High Luminosity-LHC, the CMS collaboration will replace its current calorimeter endcaps with the High Granularity Calorimeter (HGCAL) in the mid 2020s. This dissertation addresses two important topics related to the preparation of the HGCAL upgrade: experimental validation of its silicon- based design and fast simulation of its data. Beam tests at the DESY (Hamburg) and the CERN SPS beam test facilities in 2018 have been the basis for the design validation. The associated experimental infrastructure, the algorithms deployed in the reconstruction of the recorded data, as well as the respective analyses are reported in this thesis: First, core components of the silicon-based prototype modules are characterised and it is demonstrated that the assembled modules are functional. In particular, their efficiency to detect minimum ionising particles (MIPs) traversing the silicon sensors is found to be more than 98% for most of the modules. No indication of charge sharing between the silicon pads is observed. Subsequently, the energy response is calibrated in situ using the beam test data. Equalisation of the different responses among the readout channels is achieved with MIPs hereby deploying the HGCAL prototype as a MIP-tracking device. The relative variation of the inferred calibration constants amounts to 3% for channels on the same readout chip. The calibration of the time-of-arrival information is performed with an external time reference detector. With it, timing resolutions of single cells including the full prototype readout chain around 60ps in the asymptotic high energy limit are obtained. The calorimetric performance of the HGCAL prototype is validated with particle showers induced by incident positrons and charged pions. For electromagnetic showers, the constant term in the relative energy resolution is measured to be (0.52± 0.08) %, whereas the stochastic term amounts to (22.2 ± 0.3)% √GeV. This result is in good agreement with the calorimeter simulation with GEANT4. The prototype’s positioning resolution of the shower axis, after subtracting the contribution from the delay wire chambers in the beam line used as reference, is found to be below 0.4 mm at 300 GeV. At the same energy, the angular resolution in the reconstruction of the electromagnetic shower axis in this prototype is measured to be less than 5mrad. The analysis of the hadronic showers in this thesis makes use state-of-the- art machine-learning methods that exploit the calorimeter’s granularity. It is indicated that the energy resolution may be improved using software compensation and also that the separation of electromagnetic and charged pion-induced showers in the calorimeter may benefit from such methods. The measurements of the hadronic showers are adequately reproduced by GEANT4 simulation. Altogether, the obtained results from the analysis of the beam test data in this thesis are in agreement with the full functionality of the silicon-based HGCAL design. The final part of this thesis provides a proof of principle that generative modelling based on deep neural networks in conjunction with the Wasserstein distance is a suitable approach for the fast simulation of HGCAL data: Instead of sequential simulation, a deep neural network-based generative model generates all calorimeter energy depositions simultaneously. This genera t or network is optimised throu gh an adversarial training process using a critic network guided by the Wasserstein distance. The developed framework in this thesis is applied to both GEANT4- simulated electromagnetic showers and to positron data from the beam tests. Ultimately, this fast simulation approach is up to four orders of magnitude faster than sequential simulation with GEANT4. It is able to produce realistic calorimeter energy depositions from electromagnetic showers, incorporating their fluctuations and correlations when converted into typical calorimeter observables.
Publisher: Springer Nature
ISBN: 3030902021
Category : Science
Languages : en
Pages : 290
Book Description
In order to cope with the increased radiation level and the challenging pile-up conditions at High Luminosity-LHC, the CMS collaboration will replace its current calorimeter endcaps with the High Granularity Calorimeter (HGCAL) in the mid 2020s. This dissertation addresses two important topics related to the preparation of the HGCAL upgrade: experimental validation of its silicon- based design and fast simulation of its data. Beam tests at the DESY (Hamburg) and the CERN SPS beam test facilities in 2018 have been the basis for the design validation. The associated experimental infrastructure, the algorithms deployed in the reconstruction of the recorded data, as well as the respective analyses are reported in this thesis: First, core components of the silicon-based prototype modules are characterised and it is demonstrated that the assembled modules are functional. In particular, their efficiency to detect minimum ionising particles (MIPs) traversing the silicon sensors is found to be more than 98% for most of the modules. No indication of charge sharing between the silicon pads is observed. Subsequently, the energy response is calibrated in situ using the beam test data. Equalisation of the different responses among the readout channels is achieved with MIPs hereby deploying the HGCAL prototype as a MIP-tracking device. The relative variation of the inferred calibration constants amounts to 3% for channels on the same readout chip. The calibration of the time-of-arrival information is performed with an external time reference detector. With it, timing resolutions of single cells including the full prototype readout chain around 60ps in the asymptotic high energy limit are obtained. The calorimetric performance of the HGCAL prototype is validated with particle showers induced by incident positrons and charged pions. For electromagnetic showers, the constant term in the relative energy resolution is measured to be (0.52± 0.08) %, whereas the stochastic term amounts to (22.2 ± 0.3)% √GeV. This result is in good agreement with the calorimeter simulation with GEANT4. The prototype’s positioning resolution of the shower axis, after subtracting the contribution from the delay wire chambers in the beam line used as reference, is found to be below 0.4 mm at 300 GeV. At the same energy, the angular resolution in the reconstruction of the electromagnetic shower axis in this prototype is measured to be less than 5mrad. The analysis of the hadronic showers in this thesis makes use state-of-the- art machine-learning methods that exploit the calorimeter’s granularity. It is indicated that the energy resolution may be improved using software compensation and also that the separation of electromagnetic and charged pion-induced showers in the calorimeter may benefit from such methods. The measurements of the hadronic showers are adequately reproduced by GEANT4 simulation. Altogether, the obtained results from the analysis of the beam test data in this thesis are in agreement with the full functionality of the silicon-based HGCAL design. The final part of this thesis provides a proof of principle that generative modelling based on deep neural networks in conjunction with the Wasserstein distance is a suitable approach for the fast simulation of HGCAL data: Instead of sequential simulation, a deep neural network-based generative model generates all calorimeter energy depositions simultaneously. This genera t or network is optimised throu gh an adversarial training process using a critic network guided by the Wasserstein distance. The developed framework in this thesis is applied to both GEANT4- simulated electromagnetic showers and to positron data from the beam tests. Ultimately, this fast simulation approach is up to four orders of magnitude faster than sequential simulation with GEANT4. It is able to produce realistic calorimeter energy depositions from electromagnetic showers, incorporating their fluctuations and correlations when converted into typical calorimeter observables.
Calorimetry
Author: Richard Wigmans
Publisher: Oxford University Press
ISBN: 0191089699
Category : Science
Languages : en
Pages : 881
Book Description
Particle physics is the science that pursues the age-old quest for the innermost structure of matter and the fundamental interactions between its constituents. Modern experiments in this field rely increasingly on calorimetry, a detection technique in which the particles of interest are absorbed in the detector. Calorimeters are very intricate instruments. Their performance characteristics depend on subtle, sometimes counter-intuitive design details. Written by one of the world's foremost experts, Calorimetry is the first comprehensive text on this topic. It provides a fundamental and systematic introduction to calorimetry. It describes the state of the art in terms of both the fundamental understanding of calorimetric particle detection, and the actual detectors that have been or are being built and operated in experiments. The last chapter discusses landmark scientific discoveries in which calorimetry has played an important role. This book summarizes and puts into perspective the work described in some 900 scientific papers, listed in the bibliography. This second edition emphasizes new developments that have taken place since the first edition appeared in 2000.
Publisher: Oxford University Press
ISBN: 0191089699
Category : Science
Languages : en
Pages : 881
Book Description
Particle physics is the science that pursues the age-old quest for the innermost structure of matter and the fundamental interactions between its constituents. Modern experiments in this field rely increasingly on calorimetry, a detection technique in which the particles of interest are absorbed in the detector. Calorimeters are very intricate instruments. Their performance characteristics depend on subtle, sometimes counter-intuitive design details. Written by one of the world's foremost experts, Calorimetry is the first comprehensive text on this topic. It provides a fundamental and systematic introduction to calorimetry. It describes the state of the art in terms of both the fundamental understanding of calorimetric particle detection, and the actual detectors that have been or are being built and operated in experiments. The last chapter discusses landmark scientific discoveries in which calorimetry has played an important role. This book summarizes and puts into perspective the work described in some 900 scientific papers, listed in the bibliography. This second edition emphasizes new developments that have taken place since the first edition appeared in 2000.
Cosmoparticle Physics
Author: Maxim Yu Khlopov
Publisher: World Scientific
ISBN: 9789810231880
Category : Science
Languages : en
Pages : 588
Book Description
Since the 1980s the cross-disciplinary, multidimensional field of links between cosmology and particle physics has been widely recognised by theorists, studying cosmology, particle and nuclear physics, gravity, as well as by astrophysicists, astronomers, space physicists, experimental particle and nuclear physicists, mathematicians and engineers.The relationship between cosmology and particle physics is now one of the important topics of discussion at any scientific meeting both on astrophysics and high energy physics.Cosmoparticle physics is the result of the mutual relationship between cosmology and particle physics in their search for physical mechanisms of inflation, baryosynthesis, nonbaryonic dark matter, and for fundamental unity of the natural forces underlying them. The set of nontrivial links between cosmological consequences of particle models and the astrophysical data on matter and radiation in the modern universe maintains cosmoarcheology, testing self-consistently particular predictions of particle models on the base of cosmological scenarios, following from them. Complex analysis of all the indirect cosmological, astrophysical and microphysical phenomena makes cosmoparticle physics the science of the world and renders quantitatively definite the correspondence between its micro- and macroscopic structure.This book outlines the principal ideas of the modern particle theory and cosmology, their mutual relationship and the nontrivial correspondence of their physical and astrophysical effects.
Publisher: World Scientific
ISBN: 9789810231880
Category : Science
Languages : en
Pages : 588
Book Description
Since the 1980s the cross-disciplinary, multidimensional field of links between cosmology and particle physics has been widely recognised by theorists, studying cosmology, particle and nuclear physics, gravity, as well as by astrophysicists, astronomers, space physicists, experimental particle and nuclear physicists, mathematicians and engineers.The relationship between cosmology and particle physics is now one of the important topics of discussion at any scientific meeting both on astrophysics and high energy physics.Cosmoparticle physics is the result of the mutual relationship between cosmology and particle physics in their search for physical mechanisms of inflation, baryosynthesis, nonbaryonic dark matter, and for fundamental unity of the natural forces underlying them. The set of nontrivial links between cosmological consequences of particle models and the astrophysical data on matter and radiation in the modern universe maintains cosmoarcheology, testing self-consistently particular predictions of particle models on the base of cosmological scenarios, following from them. Complex analysis of all the indirect cosmological, astrophysical and microphysical phenomena makes cosmoparticle physics the science of the world and renders quantitatively definite the correspondence between its micro- and macroscopic structure.This book outlines the principal ideas of the modern particle theory and cosmology, their mutual relationship and the nontrivial correspondence of their physical and astrophysical effects.
Evolution of Silicon Sensor Technology in Particle Physics
Author: Frank Hartmann
Publisher: Springer Science & Business Media
ISBN: 3540250948
Category : Science
Languages : en
Pages : 211
Book Description
In the post era of the Z and W discovery, after the observation of Jets at UA1 and UA2 at CERN, John Ellis visioned at a HEP conference at Lake Tahoe, California in 1983 “To proceed with high energy particle physics, one has to tag the avour of the quarks!” This statement re ects the need for a highly precise tracking device, being able to resolve secondary and tertiary vertices within high-particle densities. Since the d- tance between the primary interaction point and the secondary vertex is proportional tothelifetimeoftheparticipatingparticle,itisanexcellentquantitytoidentifypar- cle avour in a very fast and precise way. In colliding beam experiments this method was applied especially to tag the presence of b quarks within particle jets. It was rst introduced in the DELPHI experiment at LEP but soon followed by all collider - periments to date. The long expected t quark discovery was possible mainly with the help of the CDF silicon vertex tracker, providing the b quark information. In the beginning of the 21st century the new LHC experiments are beginning to take 2 shape. CMS with its 206m of silicon area is perfectly suited to cope with the high luminosity environment. Even larger detectors are envisioned for the far future, like the SiLC project for the International Linear Collider. Silicon sensors matured from small 1in. single-sided devices to large 6in. double-sided, double metal detectors and to 6in. single-sided radiation hard sensors.
Publisher: Springer Science & Business Media
ISBN: 3540250948
Category : Science
Languages : en
Pages : 211
Book Description
In the post era of the Z and W discovery, after the observation of Jets at UA1 and UA2 at CERN, John Ellis visioned at a HEP conference at Lake Tahoe, California in 1983 “To proceed with high energy particle physics, one has to tag the avour of the quarks!” This statement re ects the need for a highly precise tracking device, being able to resolve secondary and tertiary vertices within high-particle densities. Since the d- tance between the primary interaction point and the secondary vertex is proportional tothelifetimeoftheparticipatingparticle,itisanexcellentquantitytoidentifypar- cle avour in a very fast and precise way. In colliding beam experiments this method was applied especially to tag the presence of b quarks within particle jets. It was rst introduced in the DELPHI experiment at LEP but soon followed by all collider - periments to date. The long expected t quark discovery was possible mainly with the help of the CDF silicon vertex tracker, providing the b quark information. In the beginning of the 21st century the new LHC experiments are beginning to take 2 shape. CMS with its 206m of silicon area is perfectly suited to cope with the high luminosity environment. Even larger detectors are envisioned for the far future, like the SiLC project for the International Linear Collider. Silicon sensors matured from small 1in. single-sided devices to large 6in. double-sided, double metal detectors and to 6in. single-sided radiation hard sensors.
Physics at the Large Hadron Collider
Author: Amitava Datta
Publisher: Springer Science & Business Media
ISBN: 8184892950
Category : Science
Languages : en
Pages : 260
Book Description
In an epoch when particle physics is awaiting a major step forward, the Large Hydron Collider (LHC) at CERN, Geneva will soon be operational. It will collide a beam of high energy protons with another similar beam circulation in the same 27 km tunnel but in the opposite direction, resulting in the production of many elementary particles some never created in the laboratory before. It is widely expected that the LHC will discover the Higgs boson, the particle which supposedly lends masses to all other fundamental particles. In addition, the question as to whether there is some new law of physics at such high energy is likely to be answered through this experiment. The present volume contains a collection of articles written by international experts, both theoreticians and experimentalists, from India and abroad, which aims to acquaint a non-specialist with some basic issues related to the LHC. At the same time, it is expected to be a useful, rudimentary companion of introductory exposition and technical expertise alike, and it is hoped to become unique in its kind. The fact that there is substantial Indian involvement in the entire LHC endeavour, at all levels including fabrication, physics analysis procedures as well as theoretical studies, is also amply brought out in the collection.
Publisher: Springer Science & Business Media
ISBN: 8184892950
Category : Science
Languages : en
Pages : 260
Book Description
In an epoch when particle physics is awaiting a major step forward, the Large Hydron Collider (LHC) at CERN, Geneva will soon be operational. It will collide a beam of high energy protons with another similar beam circulation in the same 27 km tunnel but in the opposite direction, resulting in the production of many elementary particles some never created in the laboratory before. It is widely expected that the LHC will discover the Higgs boson, the particle which supposedly lends masses to all other fundamental particles. In addition, the question as to whether there is some new law of physics at such high energy is likely to be answered through this experiment. The present volume contains a collection of articles written by international experts, both theoreticians and experimentalists, from India and abroad, which aims to acquaint a non-specialist with some basic issues related to the LHC. At the same time, it is expected to be a useful, rudimentary companion of introductory exposition and technical expertise alike, and it is hoped to become unique in its kind. The fact that there is substantial Indian involvement in the entire LHC endeavour, at all levels including fabrication, physics analysis procedures as well as theoretical studies, is also amply brought out in the collection.
Multiple Parton Interactions At The Lhc
Author: Paolo Bartalini
Publisher: World Scientific Publishing
ISBN: 981322777X
Category : Science
Languages : en
Pages : 471
Book Description
Many high-energy collider experiments (including the current Large Hadron Collider at CERN) involve the collision of hadrons. Hadrons are composite particles consisting of partons (quarks and gluons), and this means that in any hadron-hadron collision there will typically be multiple collisions of the constituents — i.e. multiple parton interactions (MPI). Understanding the nature of the MPI is important in terms of searching for new physics in the products of the scatters, and also in its own right to gain a greater understanding of hadron structure. This book aims at providing a pedagogical introduction and a comprehensive review of different research lines linked by an involvement of MPI phenomena. It is written by pioneers as well as young leading scientists, and reviews both experimental findings and theoretical developments, discussing also the remaining open issues.
Publisher: World Scientific Publishing
ISBN: 981322777X
Category : Science
Languages : en
Pages : 471
Book Description
Many high-energy collider experiments (including the current Large Hadron Collider at CERN) involve the collision of hadrons. Hadrons are composite particles consisting of partons (quarks and gluons), and this means that in any hadron-hadron collision there will typically be multiple collisions of the constituents — i.e. multiple parton interactions (MPI). Understanding the nature of the MPI is important in terms of searching for new physics in the products of the scatters, and also in its own right to gain a greater understanding of hadron structure. This book aims at providing a pedagogical introduction and a comprehensive review of different research lines linked by an involvement of MPI phenomena. It is written by pioneers as well as young leading scientists, and reviews both experimental findings and theoretical developments, discussing also the remaining open issues.
Searches for Dijet Resonances
Author: Lydia Audrey Beresford
Publisher: Springer
ISBN: 9783030073657
Category : Science
Languages : en
Pages : 0
Book Description
This book addresses one of the most intriguing mysteries of our universe: the nature of dark matter. The results presented here mark a significant and substantial contribution to the search for new physics, in particular for new particles that couple to dark matter. The first analysis presented is a search for heavy new particles that decay into pairs of hadronic jets (dijets). This pioneering analysis explores unprecedented dijet invariant masses, reaching nearly 7 TeV, and sets constraints on several important new physics models. The two subsequent analyses focus on the difficult low dijet mass region, down to 200 GeV, and employ a novel technique to efficiently gather low-mass dijet events. The results of these analyses transcend the long-standing constraints on dark matter mediator particles set by several existing experiments.
Publisher: Springer
ISBN: 9783030073657
Category : Science
Languages : en
Pages : 0
Book Description
This book addresses one of the most intriguing mysteries of our universe: the nature of dark matter. The results presented here mark a significant and substantial contribution to the search for new physics, in particular for new particles that couple to dark matter. The first analysis presented is a search for heavy new particles that decay into pairs of hadronic jets (dijets). This pioneering analysis explores unprecedented dijet invariant masses, reaching nearly 7 TeV, and sets constraints on several important new physics models. The two subsequent analyses focus on the difficult low dijet mass region, down to 200 GeV, and employ a novel technique to efficiently gather low-mass dijet events. The results of these analyses transcend the long-standing constraints on dark matter mediator particles set by several existing experiments.
Beam Acceleration In Crystals And Nanostructures - Proceedings Of The Workshop
Author: Gerard Mourou
Publisher:
ISBN: 9811217130
Category : Nanostructures
Languages : en
Pages : 269
Book Description
"Recent advancements in generation of intense X-ray laser ultrashort pulses open opportunities for particle acceleration in solid-state plasmas. Wakefield acceleration in crystals or carbon nanotubes shows promise of unmatched ultra-high accelerating gradients and possibility to shape the future of high energy physics colliders. This book summarizes the discussions of the "Workshop on Beam Acceleration in Crystals and Nanostructures" (Fermilab, June 24-25, 2019), presents next steps in theory and modeling and outlines major physics and technology challenges toward proof-of-principle demonstration experiments"--Publisher's website.
Publisher:
ISBN: 9811217130
Category : Nanostructures
Languages : en
Pages : 269
Book Description
"Recent advancements in generation of intense X-ray laser ultrashort pulses open opportunities for particle acceleration in solid-state plasmas. Wakefield acceleration in crystals or carbon nanotubes shows promise of unmatched ultra-high accelerating gradients and possibility to shape the future of high energy physics colliders. This book summarizes the discussions of the "Workshop on Beam Acceleration in Crystals and Nanostructures" (Fermilab, June 24-25, 2019), presents next steps in theory and modeling and outlines major physics and technology challenges toward proof-of-principle demonstration experiments"--Publisher's website.