共查询到20条相似文献,搜索用时 62 毫秒
1.
Chong-Xing Yue Nan Zhang Shi-Hai Zhu 《The European Physical Journal C - Particles and Fields》2008,53(2):215-219
The littlest Higgs model with T-parity predicts the existence of the T-odd particles, which can only be produced in pairs.
We consider pair production of the T-odd leptons in a future high energy linear e+e- collider (ILC). Our numerical results show that, as long as the T-odd leptons are not too heavy, they can be copiously produced
and their possible signals might be detected via the processes e+e-→L̄iLj in future ILC experiments. 相似文献
2.
N. Yongram 《International Journal of Theoretical Physics》2011,50(3):838-849
Spin correlations of e
+
e
− pair productions of two colliding photons are investigated and explicit expressions for their corresponding probabilities
are derived and found to be energy (speed) dependent, for initially linearly and circularly polarized photons, different from those obtained by simply combining the spins of the relevant particles, for initially polarized photons. These expressions also depend on the angles of spin of e
+ (and/or of e
−), for initially linearly polarized photons, but not for circularly polarized photons, as a function of the energy. It is remarkable that these explicit results obtained from quantum field theory show
a clear violation of Bell’s inequality of Local Hidden Variables theories at all energies beyond that of the threshold one for particle production, in support of quantum field theory in the relativistic regime.
We hope that our explicit expression will lead to experiments, of the type described in the bulk of this paper, which can
monitor energy (and speed) in polarization correlation experiments. 相似文献
3.
We consider semi-inclusive unpolarized DIS for the production of charged kaons and the different possibilities to test the
conventionally used assumptions s-s̄=0 and Dd
K+-K-=0. The tests considered have the advantage that they do not require any knowledge of the fragmentation functions. We also
show that measurements of both charged and neutral kaons would allow for the determination of the kaon fragmentation functions
Dq
K++K- solely from SIDIS measurements, and we discuss the comparison of (Du-Dd)K+-K- obtained independently in SIDIS and e+e- reactions. All analyses are performed in LO and NLO in QCD. The feasibility of the tests to HERMES SIDIS data is considered.
PACS 12.38.Bx; 13.85.Ni 相似文献
4.
Xuelei Wang Yaobei Liu Jihong Chen Hua Yang 《The European Physical Journal C - Particles and Fields》2007,49(2):593-597
The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs
model, we study the process e+e-→e+e-H at the ILC and calculate the correction of the littlest Higgs model to the cross section of this process. The results show
that, in the favorable parameter spaces preferred by the electroweak precision data, the value of the relative correction
is in the range from a few percent to tens percent. In most cases, the correction is large enough to reach the measurement
precision of the ILC. Therefore, the correction of the littlest Higgs model to the process e+e-→e+e-H might be detected at the ILC, which will give an ideal way to test the model.
PACS 12.60.Nz; 14.80.Mz; 12.15.Lk; 14.65.Ha 相似文献
5.
The influence of phosphate glass electrode in the configuration of resistive plate chamber has been studied using GEANT3.21
Monte Carlo code. Bakelite electrodes were replaced by phosphate glass electrodes, as these glass materials have low bulk
resistivity, are portable and easy to handle. These types of RPCs in their compact form of all materials are suitable for
high rate background environment. We find that these new types of RPCs give little higher response to γ-rays and e+/e− particles, both for single-and double gap RPCs. The results of simulation are discussed.
相似文献
6.
Santosh Kumar Rai 《Pramana》2007,69(5):815-818
Loop-driven decay modes of the Higgs are sensitive to new physics contributions because of new particles in the loops. To
highlight this we look at the dilepton-dijet signal in the dominant Higgs production channel at a linear e
+
e
− collider. We show that by taking a simple ratio between cross-sections of two different final states such contributions can
be very easily identified.
相似文献
7.
N. Oshimo 《The European Physical Journal C - Particles and Fields》2005,39(3):383-388
The measurability of generation mixing is studied on pair production of sneutrinos in e
+
e
- collisions and their subsequent decays into two different charged leptons e and μ with two lighter charginos. The analyses are made systematically in a general framework of the supersymmetric extension
of the standard model. The production and decay process depends on the parameters of the chargino sector as well as those
of the sneutrino sector. Although generation-changing interactions are severely constrained by radiative charged-lepton decays,
sizable regions in the parameter space could still be explored at e
+
e
- colliders in the near future.
Received: 6 October 2004, Revised: 14 November 2004, Published online: 14 January 2005
PACS:
11.30.Hv, 12.15.Ff, 12.60.Jv, 14.80.Ly 相似文献
8.
A.E. Dorokhov E.A. Kuraev Yu.M. Bystritskiy M. Sečanský 《The European Physical Journal C - Particles and Fields》2008,55(2):193-198
We reconsider QED radiative corrections (RC) to the π0→e+e- decay width. One kind of RC investigated earlier has a renormalization group origin and can be associated with the final
state interaction of electron and positron. It determines the distribution of lepton pair invariant masses in the whole kinematic
region. The other type of RC has a double-logarithmic character and is related to almost on-mass-shell behavior of the lepton
form factors. The total effect of RC for π0→e+e- decay is estimated to be 3.2%, and for η→e+e- decay it is 4.3%.
PACS 13.25.Cq; 12.38.Lg; 12.38.-t 相似文献
9.
A. Gay 《The European Physical Journal C - Particles and Fields》2007,49(2):489-497
Understanding the mechanism of electroweak symmetry breaking and the origin of boson and fermion masses is among the most
pressing questions raised in contemporary particle physics. If these issues involve one (several) Higgs boson(s), a precise
measurement of all its (their) properties will be of prime importance. Among those, the Higgs coupling to matter fermions
(the Yukawa coupling). At a linear collider, the process e+e-→tt̄H will allow a direct measurement of the top-Higgs Yukawa coupling. We present a realistic feasibility study of the measurement
in the context of the TESLA collider. Four channels are studied and the analysis is repeated for several Higgs mass values
within the range 120–200 GeV/c
2.
PACS 13.66.Jn; 14.65.Ha; 14.80.Bn 相似文献
10.
We have investigated the doubly excited 1,3
P
e resonance states of positronium negative ion with Coulomb and screened Coulomb potentials using highly accurate correlated
exponential wavefunctions. For Coulomb interaction, the stabilization and the complex-rotation methods are employed to extract
resonance parameters (resonance positions and widths). We have obtained two 1
P
e resonances and three 3
P
e resonances below the n = 3 Ps threshold. In addition to Feshbach resonances lying below n = 3 Ps threshold, we have calculated one 3
P
e shape resonances lying above the Ps (n = 2) threshold. For screened Coulomb (Yukawa) interaction, we employ the stabilization method to extract resonance parameters
as functions screening parameter. The resonance energies and widths for 1,3
P
e resonance states of Ps− below the n = 3 Ps threshold for different screening parameters ranging from infinity (Coulomb case) to small values are reported, along
with the Ps(3S) and Ps(3P) threshold energies. The screened Coulomb results for the 1,3
P
e resonance states are reported for the first time in the literature. 相似文献
11.
A.A. Bagneid 《The European Physical Journal C - Particles and Fields》2008,54(4):547-553
We examine distributions of leptons produced in e+e- collisions, by a family nonuniversal extra gauge boson Z′, suggested by the model, and by other neutral gauge bosons occurring in left–right symmetric models and in superstring-inspired E6 models. We discuss how to distinguish the models by examining the couplings to fermions of the extra Z-boson through its
leptonic production cross sections and asymmetries. We show how the universality violation inherent in the model enhances the discovery potential of Z′ at future planned and proposed e+e- colliders. 相似文献
12.
R.M. Godbole S.K. Rai S. Raychaudhuri 《The European Physical Journal C - Particles and Fields》2007,50(4):979-990
The electromagnetic radiation emitted by colliding beams is expected to play an important role at the next generation of high
energy e+e- linear colliders. Focussing on the simplest process, e+e-→μ+μ-, we show that, for suitable machine parameters and luminosity, radiative effects like initial state radiation (ISR) and beamstrahlung
can be used to search for resonant graviton modes of the Randall–Sundrum model in an efficient manner. 相似文献
13.
The multiple hadron production in the events induced by the heavy primary quarks in e+e- annihilation is reconsidered with account of corrected experimental data. A new value for the multiplicity in bb̄ events
is presented on the basis of pQCD estimates. 相似文献
14.
M. Schwamb S. Boffi C. Giusti F.D. Pacati 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):7-10
The influence of the mutual interaction between the two outgoing nucleons (NN-FSI) in the 16O(e, e'pp) reaction has been investigated. Results for various kinematics are discussed. In general, the effect of NN-FSI depends on
kinematics and the chosen final state in the excitation spectrum of 14C.
Received: 19 December 2002 / Accepted: 6 February 2003 / Published online: 15 April 2003 相似文献
15.
N. Kaiser 《The European Physical Journal A - Hadrons and Nuclei》2007,31(2):207-212
We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the leading-order 2π exchange
NN interaction proportional to g
A
0 and g
A
2. The resulting 2πγ exchange potential contains isospin-breaking components which reach up to about -2% of the corresponding
isovector 2π exchange potential. With a value of only -17keV at r = m
π
-1 = 1.4fm the charge-independence breaking central potential obtained here is negligibly small in comparison to the one generated
by the isoscalar c3 contact vertex. Our calculation confirms that the largest long-range isospin-violating NN potentials arise from the 2πγ exchange diagrams involving the large low-energy constants c
4 ≃ - c
3 ≃ 3.3GeV^-1 representing the important Δ(1232) dynamics. 相似文献
16.
X. G. Wu M. J. Wan C. Q. Song T. Gao 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(2):263-267
Electronic structure and spectroscopic properties B
e, ωe, ωe
x
e, αe, T
e
of ground state and the low-lying excited states of HF+ and HF- molecular ions were
investigated within scalar relativistic multireference configuration
interaction with single and double excitations framework using the GAMESS-US
program package. All potential energy curves (PECs) were calculated using
the relativistic complete active space self-consistent field/spin-orbit
multi-configuration quasi-degenerate perturbation theory (CASSCF/SO-MCQDPT).
The curves are all fitted to the analytical potential energy function
(APEF), from which accurate spectroscopic constants are derived. The
spin-orbit splitting was also been studied, the split value of X2P^{2}{\rm \Pi} state of HF+ is determined to be 288.38 cm-1. The calculated properties are in good agreement with the available experimental value.
Spectroscopic constants of the ground states of HF- that have never
been observed in experiment are obtained. These curves provide an
interpretation of the known experimental observations on this system and
suggest a number of further experiments which possible provide a critical
test of this data. 相似文献
17.
Complementing the preceding study of charged scalar leptons, the sector of the neutral scalar leptons, sneutrinos, is investigated in a high-precision analysis for future e
+
e
- linear colliders. The theoretical predictions for the cross-sections are calculated at the thresholds for non-zero widths and in the continuum including higher-order corrections at the one-loop level. Methods for measuring the sneutrino masses and the electron-sneutrino-gaugino Yukawa couplings are presented, addressing theoretical problems specific for the sneutrino channels.Received: 10 September 2004, Revised: 11 October 2004, Published online: 3 March 2005 相似文献
18.
Doubly-charged scalars, predicted in many models having exotic Higgs rep-resentations, can in general have lepton-number violating
(LFV) couplings. We show that by using an associated monoenergetic final state photon seen at a future linear e
−
e
− collider, we can have a clear and distinct signature for a doubly-charged resonance. The strength of the ΔL = 2 coupling can also be probed quite effectively as a function of the recoil mass of the doubly-charged scalar.
相似文献
19.
A. Liebsch H. Ishida 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(4):405-411
There exists presently considerable debate over the question whether
local Coulomb interactions can explain the absence of the small e′
g
Fermi surface hole pockets in photoemission studies of Na0.3CoO2.
By comparing dynamical mean field results for different single particle
Hamiltonians and exact diagonalization as well as quantum Monte Carlo
treatments, we show that, for realistic values of the Coulomb energy U
and Hund exchange J, the e′
g pockets can be slightly enhanced or
reduced compared to band structure predictions, but they do not disappear. 相似文献
20.
The top-pions (Πt
0,±) and the top-Higgs (ht
0) are the typical particles predicted by the topcolor-assisted technicolor (TC2) model and the observation of these particles
can be regarded as direct evidence of the TC2 model. In this paper, we study three pair production processes of these new
particles at the next generation eγ colliders, i.e., e-γ→e-Πt
+Πt
-, e-γ→νeΠt
-Πt
0 and e-γ→νeΠt
-ht
0. The results show that the production rates can reach the level 100–101 fb with reasonable parameter values. So one can expect that enough signals could be produced in future high- energy linear
collider experiments. Furthermore, the flavor-changing (FC) decay modes Πt
-→bc̄, Πt
0(ht
0)→tc̄ can provide us with the typical signal to detect these new particles.
PACS 12.60Nz; 14.80.Mz; 12.15.LK; 14.65.Ha 相似文献