119401628
The Electron Cooling Device for LEAR
The experiments1,2,3 in which low energetic protons were cooled by a “cold” electron beam have proved that this method is a very powerful technique to improve low energy beams and to increase their phase space density by several orders of magnitude in short times. The theoretical understanding of the cooling process is well advanced4,5,6. The applications of this technique, which was invented and developed in Novosibirsk, are manifold7. It seems to be clear that its main domain is the cooling of non-relativistic ions. However, also at extremely high energies, cooling of protons and antiprotons with stored electrons (cooled themselves by synchrotron radiation) can be contemplated8,9.
102555920
The LHC Lead Ion Injector Chain
121692361
First results of electron cooling experiments at LEAR
The first results are presented of electron cooling experiments in the Low-Energy Antiproton Ring (LEAR) at CERN, performed with a proton beam of about 50 and 21 MeV. The number of stored protons ranged from 107 to 3 × 109. Cooling times of the order 1 s and proton drag rates of up to 0.7 MeV/s were obtained. The capture of cooling electrons by protons producing hydrogen atoms was used to derive an effective electron temperature (0.25 eV). From the angular profile of the neutral hydrogen beam an upper limit of 3π mm.mrad could be deduced for the horizontal equilibrium proton-beam emittance. The lowest equilibrium momentum spread was 2 × 105 (FWHM), as derived from the analysis of the longitudinal Schottky signal. This Schottky signal exhibited an unusual behaviour with beam intensity and under certain conditions showed a doublepeak structure which was associated with collective beam noise. For very cold beams transverse instabilities were observed, which resulted in a rapid spill-off of protons and a stabilization at lower intensities. The threshold of these instabilities was raised by heating the proton or the electron beam. The cooling of a bunched proton beam was investigated. The reduction of the proton momentum spread led to bunch lengths of about 2 m, containing 3 × 108 protons.
137745598
Concept for a lead-ion accelerating facility at CERN
55444273
Present Performance of the CERN Proton Linac
The original 1973 design specification of the CERN 50 MeV Proton Linac was for a 150 mA beam but this intensity was rarely used. Preliminary tests for the high brightness beam required for LHC indicated that 170 mA could be produced for short pulses (30 Ps). Since then further optimisation has enabled the 170 mA to be delivered reliably, within the nominal emittances and dispersion, in long pulses (120 Ps) to the user, the PS Booster (PSB), about 80 m downstream of the linac. The improvements will be described along with the steps envisaged to attain a goal of more than 180 mA.
115300845
Status and first beam measurements on the CERN RFQ
120478961
Moving mirrors in Schrödinger picture
Abstract We formulate the problem of accelerating mirrors upon which quantum fields satisfy Dirichlet boundary conditions, with the associated Hawking effect, in a functional Schrodinger picture. Systems of this kind model some aspects of gravitational collapse leading to the formation of a black-hole. The criterion for the non-separability of the mode expansion in space- and time-dependences is the non-vanishing of a certain second-rank antisymmetric functional, the analogue of an electromagnetic field strength. Arbitrarily moving mirrors involves the functional analogue of the quantum mechanics of a charged particle in an external magnetic field. It is solved explicitly for a special case corresponding to the analogue of gravitational collapse.
117978488
Fixed Points: Fermion Mass Predictions
Familiar theoretical relationships exist amongst the masses of the light fermions in SU(5):1 
 
$$ \frac{{{m_d}}}{{{m_e}}} \approx \frac{{{m_s}}}{{{m_{\mu }}}} \simeq 4\pm \frac{\hbox{$\scriptstyle 1$}}{\hbox{$\scriptstyle 2$}} \quad \frac{{{m_b}}}{{{m_{\tau }}}} \simeq 2.75\pm .25 $$ 
 
These result from essentially three ingredients: (a) the Higgs mechanism which relates the fermion mass to the Higgs-Yukawa (HY) coupling constant by \( {m_f} = {g_f} /\sqrt {2} \approx {g_f} \cdot (175\quad GeV) \) (b) the renormalization group (RG) equations which describe the evolution of the (HY) couplings down from MX to low energies and (c) the boundary conditions from SU(5), assuming a 5 and 24 of Higgs, which relate g−1/3 quark (MX) = g−1 lepton (MX) within a given generation. Thus one obtains: 
 
$$ \frac{{^{m} - 1/3}}{{^{m} - 1}} = \frac{{^{g} - 1/{{3}^{{(\mu )}}}}}{{^{g} - {{1}^{{(\mu )}}}}} \approx {{\left( {\frac{{{{\alpha }_{3}}\left( \mu \right)}}{{{{\alpha }_{3}}\left( {{{M}_{X}}} \right)}}} \right)}^{{8/2{{b}_{0}}}}} + {{\left. {\left( {electroweak} \right)} \right|}_{{\mu \simeq {{m}_{{quark}}}}}} $$ 
 
(2) 
 
and the numerical results of eq. (1) follow to one loop accuracy with Λs ~. 4 GeV. We note that ingredients (b) and (c) do not apply to models with composite Higgs bosons (e.g. ETC) or composite fermions on a scale of M′ < MX since the RG equations demand pointlike particles over the entire range of the desert. Though the results for md/me and ms/mμ are questionable we note that they are qualitatively correct. We take the “prediction” for mb/mτ to be a successful result of SU(5) and we seek to extend the above analysis to much heavier objects; either a very heavy top-quark or a heavy fourth generation of quarks and leptons.
14139978
THE DIFFRACTIVE QUANTUM LIMITS OF PARTICLE COLLIDERS
Quantum Mechanics places limits on achievable transverse beam spot sizes of particle accelerators. We estimate this limit for a linear collider to be \Delta x > \hbar c f/E\delta_0 where f is the final focal length, E the beam energy, and \delta_0 the intrinsic transverse Gaussian width of the electron wave-function. \delta_0 is determined in the phase space damping rings, and we find \delta_0 \approx \sqrt{\hbar c /eB} where B is the typical wiggler magnetic field strength in this system. For the NLC \delta_0 = 25 nm, and \Delta x = 0.06 nm, about two orders of magnitude smaller than the design goal. We can recover a crude estimate of the classical result when we include radiative relaxation effects. We also consider a synchrotron and obtain \Delta x > \sqrt{\hbar c f/E} = O(1.0) nm. We discuss formulation of quantum beam optics relevant to these issues.
122396660
Theoretical Expectations for Mass Scales of the Fourth Generation and Higgs Bosons
We discuss two classes of theories that have something to say about fourth generation quark and lepton masses (as well as Higgs). One is based upon universality of low energy parameters as determined by the renormalization group: infra-red fixed points. The other is a toy model of geometric heirarchy which may arise in a novel scheme of dimensional reduction without compactification.
122678636
One Loop Operator Matrix Elements in the Unruh Vacuum
Abstract We present the details of a study of the matrix elements of local operators in the Unruh vacuum for real massive scalar fields in arbitrary d -spatial dimensions (also the Casimir effects for an infinite plane conductor). This state produces negative expectations for renormalized operators such as φ 2 and T μν with the structure of thermal corrections where the temperature is a local Hawking temperature. We trace this to the lack of precise boundary conditions for the theory on the horizon. Though the Minkowski vacuum appears to be populated with Rindler particles, it produces the general coordinate transform of the Minkowski results as dictated by general covariance. A simple corollary is that broken symmetries are not seen to be restored at large acceleration; the dynamical interpretation of this fact by the accelerating observer is surprising.