2,346 research outputs found
LHC/ILC Interplay in SUSY Searches
Combined analyses at the Large Hadron Collider and at the International
Linear Collider are important to reveal precisely the new physics model as, for
instance, supersymmetry. Examples are presented where ILC results as input for
LHC analyses could be crucial for the identification of signals as well as of
the underlying model. The synergy of both colliders leads also to rather
accurate SUSY parameter determination and powerful mass constraints even if the
scalar particles have masses in the multi-TeV range.Comment: 5 pages, contribution to the proceedings of EPS0
Strong field effects on physics processes at the Interaction Point of future linear colliders
Future lepton colliders will be precision machines whose physics program
includes close study of the Higgs sector and searches for new physics via
polarised beams. The luminosity requirements of such machines entail very
intense lepton bunches at the interaction point with associated strong
electromagnetic fields. These strong fields not only lead to obvious phenomena
such as beamstrahlung, but also potentially affect every particle physics
process via virtual exchange with the bunch fields. For precision studies,
strong field effects have to be understood to the sub-percent level. Strong
external field effects can be taken into account exactly via the Furry Picture
or, in certain limits, via the Quasi-classical Operator method . Significant
theoretical development is in progress and here we outline the current state of
play.Comment: 6 pages, ICHEP 2012 Proceeding
Beam Polarization and Spin Correlation Effects in Chargino Production and Decay
We study chargino production e^+ e^- -> chi^+_1 chi^-_1 and the subsequent
leptonic decay chi^-_1\to chi^0_1 e^- nu_e including the complete spin
correlations between production and decay. We work out the advantages of
polarizing the e^+ and e^- beams. We study in detail the polarized cross
sections, the angular distribution and the forward--backward asymmetry of the
decay electron. They can be used to determine the sneutrino mass
m_{\tilde{\nu}_e}.Comment: 14 pages, 17 postscript figures, latex using epsfi
Photon collimator system for the ILC Positron Source
High energy e+e- linear colliders are the next large scale project in
particle physics. They need intense sources to achieve the required luminosity.
In particular, the positron source must provide about 10E+14 positrons per
second. The positron source for the International Linear Collider (ILC) is
based on a helical undulator passed by the electron beam to create an intense
circularly polarized photon beam. With these photons a longitudinally polarized
positron beam is generated; the degree of polarization can be enhanced by
collimating the photon beam. However, the high photon beam intensity causes
huge thermal load in the collimator material. In this paper the thermal load in
the photon collimator is discussed and a flexible design solution is presented.Comment: 22 pages, 19 figures, 8 tables, cross-reference to table 4 fixe
Impact of e^+ and e^- Beam Polarization on Chargino and Neutralino Production at a Linear Collider
We study the production processes e^+ e^- -> chi^+_i chi^-_j, i,j=1,2, and
e^+ e^- -> chi^0_m chi^0_n, m,n=1,...,4, working out the advantages of
polarizing both beams. For e^+ e^- -> chi^+_1 chi^-_1 with chi^-_1 -> chi^0_1
e^- nu and e^+ e^- -> chi^0_1 chi^0_2 with chi^0_2 -> chi^0_1 e^+ e^- we
perform a detailed analysis, including the complete spin correlations between
production and decay. We analyze the forward--backward asymmetry of the decay
electron for various beam polarizations. We also study polarization asymmetries
in e^+ e^- -> chi^0_1 chi^0_2. These asymmetries strongly constrain the gaugino
parameter M_1 and the masses m_{\tilde{e}_L}, m_{\tilde{e}_R}, m_{\tilde{nu}}
also if m_{\tilde{e}_{L,R}}, m_{\tilde{nu}} > sqrt{s}/2. We give numerical
predictions for three scenarios for a linear collider with sqrt{s}=500-1000
GeV.Comment: 26 pages, 26 postscript figures, latex using epsfi
Exploiting Spin Correlations in Neutralino Production and Decay with Polarized e^- and e^+ Beams
We study the production process e^+ e^- -> chi^0_1 chi^0_2 and the subsequent
decay chi^0_2 -> chi^0_1 l^+ l^- with polarized e^+ and e^- beams, including
the spin correlations between production and decay. We work out the advantages
of polarizing both beams. We study in detail the angular distribution and the
forward--backward asymmetry of the decay lepton as well as the opening angle
distribution between the decay leptons. We investigate the dependence on the
masses of tilde{e}_L and tilde{e}_R and on the mixing character of the
neutralinos. In particular we study the dependence on the gaugino mass
parameter M_1.Comment: 17 pages, 14 postscript figures, latex using epsfi
Quantitative test of general theories of the intrinsic laser linewidth
We perform a first-principles calculation of the quantum-limited laser
linewidth, testing the predictions of recently developed theories of the laser
linewidth based on fluctuations about the known steady-state laser solutions
against traditional forms of the Schawlow-Townes linewidth. The numerical study
is based on finite-difference time-domain simulations of the semiclassical
Maxwell-Bloch lasing equations, augmented with Langevin force terms, and thus
includes the effects of dispersion, losses due to the open boundary of the
laser cavity, and non-linear coupling between the amplitude and phase
fluctuations ( factor). We find quantitative agreement between the
numerical results and the predictions of the noisy steady-state ab initio laser
theory (N-SALT), both in the variation of the linewidth with output power, as
well as the emergence of side-peaks due to relaxation oscillations.Comment: 24 pages, 10 figure
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