First generation interferometers

The status and plans for the first generation long baseline suspended mass interferometers TAMA, GEO, LIGO and Virgo are presented, as well as the expected performances

Amaldi Meeting Introduction

Welcome to Caltech and the 3rd Edoardo Amaldi Conference on Gravitational Waves. Obviously, something must be very interesting to bring more than 250 scientists from around the world to Pasadena in July for this particular meeting. In fact, July in Southern California does have many attractions, in addition to the good weather and cool nights. For this conference, we have arranged a visit to the new Getty Museum on our excursion day. This is meant to make your stay more pleasant, but is not the real reason we have gathered here. This meeting addresses the detection of gravitational waves, a much-anticipated event

The International Linear Collider

In this article, we describe the key features of the recently completed technical design for the International Linear Collider (ILC), a 200-500 GeV linear electron-positron collider (expandable to 1 TeV) that is based on 1.3 GHz superconducting radio-frequency (SCRF) technology. The machine parameters and detector characteristics have been chosen to complement the Large Hadron Collider physics, including the discovery of the Higgs boson, and to further exploit this new particle physics energy frontier with a precision instrument. The linear collider design is the result of nearly twenty years of R&D, resulting in a mature conceptual design for the ILC project that reflects an international consensus. We summarize the physics goals and capability of the ILC, the enabling R&D and resulting accelerator design, as well as the concepts for two complementary detectors. The ILC is technically ready to be proposed and built as a next generation lepton collider, perhaps to be built in stages beginning as a Higgs factory.Comment: 41 page

Nobel Lecture: LIGO and gravitational waves II

The observation of gravitational waves (see Fig. 1) in the Laser Interferometer Gravitational-wave Observatory (LIGO) was announced on 11 February 2016 (Abbott et al., 2016a), 100 years after Einstein proposed the existence of gravitational waves (Einstein, 1916, 1918). This observation came after more than 50 years of experimental efforts to develop sensitive enough detectors to observe the tiny distortions in spacetime from gravitational waves. The Nobel Prize for 2017 was awarded to Rainer (“Rai”) Weiss, Kip Thorne and myself for decisive contributions to the LIGO detector and the observation of gravitational waves. In fact, the success of LIGO follows from decades of R&D on the concept and techniques, which were covered in Rai Weiss’ Nobel Lecture, followed by the design, construction and evolving the LIGO large-scale interferometers to be more and more sensitive to gravitational waves. This work has been carried through the LIGO Laboratory and the scientific exploitation through the LIGO Scientific Collaboration, having more than 1000 scientists, who author the gravitational wave observational papers. In addition, many others made important contributions to the science of black holes, numerical relativity, etc

Interview with Barry C. Barish

Interview in five sessions, May-July 1998, with Barry C. Barish, Linde Professor of Physics emeritus and director of LIGO [Laser Interferometer Gravitational-Wave Observatory] 1994-2005. Recalls undergraduate education, Berkeley; graduate work on Lawrence Radiation Laboratory cyclotron; postdoc work on bevatron. Meets Alvin Tollestrup, comes to Caltech as postdoc, 1963. At Brookhaven National Laboratory. At Stanford Linear Accelerator Center with Henry Kendall, Richard Taylor, and Jerome Friedman. With Frank Sciulli, proposes neutrino experiment for Fermilab; work on tau leptons at SLAC. Move to Cornell. Discusses history of magnetic monopoles and his work on monopoles at Caltech in 1980s. Discusses history of SSC [Superconducting Super Collider]; problems with Standard Model of Particle Physics; Aspen conferences to plan SSC; selection of Texas site. Involvement of Samuel C. C. Ting. Devises SSC experiment, with W. J. Willis. SSC's defeat in Congress (1993). Discusses his work in Italy on monopoles, in Gran Sasso tunnel. MACRO [Monopole Astrophysics Cosmic Ray Observatory] detector. Discusses history of LIGO. Bar detector experiments of Joseph Weber. Initial meetings at Caltech. Hiring of Ronald W. P. Drever. Rochus E. (Robbie) Vogt as head, 1987. Disastrous technical review and project review, 1992-93. He takes project over from Vogt in February 1994. Discusses problems he encountered and lack of evolution between 1989 and 1994. Discusses LIGO's technical difficulties and evolution of its organizational structure. LIGO Laboratory and LIGO (construction) Project. Establishment of LIGO Scientific Collaboration. Comments on Caltech; disinclination to serve on committees, enjoyment of teaching. Recollections of Richard Feynman. Influence of Tollestrup and Taylor

Optimal Strategies for Sinusoidal Signal Detection

We derive and study optimal and nearly-optimal strategies for the detection of sinusoidal signals hidden in additive (Gaussian and non-Gaussian) noise. Such strategies are an essential part of algorithms for the detection of the gravitational Continuous Wave (CW) signals produced by pulsars. Optimal strategies are derived for the case where the signal phase is not known and the product of the signal frequency and the observation time is non-integral.Comment: 18 pages, REVTEX4, 7 figures, 2 table

Particle astrophysics

The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented

High Energy & High Luminosity γγ\gamma\gamma Colliders

With the best of modern standard lasers, high-energy $\gamma\gamma$ colliders from electron beams of E larger than 250 GeV are only possible at the expense of photon luminosity, i.e. 10 times lower than for photon colliders at c.m. energies below 0.5 TeV. For existing state-of-the art lasers, an optimistic upper energy limit for x=4.8 is an electron beam of less than 250 GeV. This Snowmass21 Contributed Paper shows how Free Electron Lasers (FEL) pave the way for High Energy & High Luminosity $\gamma\gamma$ colliders. We present and assess a conceptual design study of a FEL with wavelength of 2.4 $\mu$m and an x-factor in the range of 2 to 40, to maximize the luminosity of a $\gamma\gamma$ collider as second interaction region of 0.5 TeV to 10 TeV c.m. $e^+e^-$ colliders.Comment: Contribution to Snowmass 202

Inelastic π--p Interactions in the Energy Region of 310 to 454 MeV

Differential cross sections for positive pions, protons, and neutrons resulting from inelastic π--p collisions have been measured from 310- to 454-MeV incident-pion kinetic energy. The data were obtained with electronic counter systems, which measured the energy distribution of the final-state particle of interest at a series of fixed angles. The results have been interpreted in terms of the final states π+π-n, π0π0n, and π-π0p. The total cross sections for these three modes as a function of incident pion energy are in qualitative agreement with the predictions by Schnitzer. A preference is shown for his set of π-π scattering lengths; a0=0.65, a1=0.07, and a2=-0.14μ-1. The observed neutron distributions correspond to a strong preference for low c.m.-system neutron energies in both the π+π-n and π0π0n final states. The effect is not present in the observed proton distributions from the π-π0p reaction, which suggests that it is due to a I=0, π-π interaction. The π+ data show the formation of the (3,3) isobar combination of the π--n system in the π+π-n final state. Analysis in terms of an isobar model indicates the predominance of I=1/2 incident state