337 research outputs found
Notes about collision monochromatization in colliders
The manuscript describes several monochromatization schemes starting from
A.~Renieri \cite{ref:Renieri} proposal for head-on collisions based on
correlation between particles transverse position and energy deviation. We
briefly explain initial proposal and expand it for crossing angle collisions.
Then we discuss new monochromatization scheme for crossing angle collisions
based on correlation between particles longitudinal position and energy
deviation
Beam-beam effects investigation and parameters optimization for a circular e+e- collider TLEP to study the Higgs boson
Several proposals exist for future circular electron-positron colliders
designed for precise measurements of the Higgs boson characteristics and
electroweak processes. At very high energies, synchrotron radiation of the
particles in a strong electromagnetic field of the oncoming bunch
(beamstrahlung) becomes extremely important, because of degradation of the beam
lifetime and luminosity. We present theoretical calculations of beamstrahlung
(including the beam lifetime reduction and the energy spread increase) which
are benchmarked against quasi strong-strong computer simulation. Calculation
results are used to optimize TLEP project (CERN).Comment: 17 pages, 2 tables, 9 figure
Dynamic aperture limitation in colliders due to synchrotron radiation in quadrupoles
In a lepton storage ring of very high energy (e.g. in the Higgs
factory) synchrotron radiation from quadrupoles constrains transverse dynamic
aperture even in the absence of any magnetic nonlinearities. This was observed
in tracking for LEP and the Future Circular Collider (FCC-ee). Here we
describe a new mechanism of instability created by modulation of the particle
energy at the double betatron frequency by synchrotron radiation in the
quadrupoles. Energy modulation varies transverse focusing strength at the same
frequency and creates a parametric resonance of the betatron oscillations with
unusual properties. It occurs at arbitrary betatron frequency (the resonant
detuning is always zero) and the magnitude of the parameter modulation of the
betatron oscillation (strength of the resonance driving term) depends on the
oscillation amplitude. Equilibrium between the radiation damping and the
resonant excitation gives the boundary of the stable motion. Starting from 6d
equations of motion we derive and solve the relevant differential equation
describing the resonance, and show good agreement between analytical results
and numerical simulation
Effect of the superconducting wiggler on the DELSY beam dynamics
The project DELSY is being under development at JINR, Dubna, Russia. This
synchrotron radiation source is dedicated to the investigation on condensed
matter physics, atomic physics, biology, medicine, chemistry, micromechanics,
lithography and others. The storage ring DELSY is an electron storage ring with
the beam energy 1.2 GeV and 4 straight sections to accommodate accelerator
equipment and insertion devices. One of the straight sections is intended for a
10 T superconducting wiggler (wavelength shifter) and one for the undulator
with 150 periods and a magnetic field of 0.75 T. The wiggler will influence
many aspects of beam dynamics: linear motion, dynamic aperture, emittance,
damping times etc. The problem is rather serious for the DELSY machine because
the energy of the electron beam is small while the wiggler's magnetic field is
strong. In this paper we consider two models of the wiggler's magnetic field
with and without the focusing caused by the sextupolar field of the wiggler as
we need to develop the requirements to the wiggler design. We study the
influence of the 10 T wiggler on the beam dynamics in the DELSY storage ring
and propose a possible scheme to cure it. The combined work of the insertion
device is presented too.Comment: 17 pages, submitted to journal NIM
Towards a matrix multi-level model of quark-gluon media
The key feature of the model is an infinite sequence of canonical immersions of groups: U(2) into U(3), U(2) into U(4), and so on. Let us refer to these groups as to levels: U(2) – the 0th level (that is, ours common), U(3) – the 1st, U(4) – the 2nd and so on. Levels relate to (quarks’) generations whereas flavor and color are also defined purely mathematically. According to the model, quarks can be interpreted as ‘sank’ protons (during the beginning of the reaction process, proton (or rather the support U(2) of its wave function) is merely pushed into a deeper level. The model seems to be compatible with detection of point-like constituents within the proton in highly inelastic electron-proton scattering (and with elastic electron-quark scattering). To introduce gluons, we deal with proton-antiproton pairs (tensor product). At each level, a gluon can be interpreted as a colored photon. Not each and every feature of the model coincides with the corresponding standard assumption about quarks and gluons. In particular, the total number of colors is level-dependent. The model predicts three new quarks (of the 4th generation)
- …