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1.
A. Freitas A. von Manteuffel P. M. Zerwas 《The European Physical Journal C - Particles and Fields》2004,34(4):487-512
High-precision analyses are presented for the production of scalar sleptons, selectrons and smuons in supersymmetric theories, at future e + e- and e-e- linear colliders. Threshold production can be exploited for measurements of the selectron and smuon masses, an essential ingredient for the reconstruction of the fundamental supersymmetric theory at high scales. The production of selectrons in the continuum will allow us to determine the Yukawa couplings in the selectron sector, scrutinizing the identity of the Yukawa and gauge couplings, which is a basic consequence of supersymmetry. The theoretical predictions are elaborated at the one-loop level in the continuum, while at threshold non-zero width effects and Sommerfeld rescattering corrections are included. The phenomenological analyses are performed for e + e- and e-e- linear colliders with energy up to about 1 TeV and with high integrated luminosity up to 1 ab-1 to cover the individual slepton channels separately with high precision.Received: 21 October 2003, Revised: 12 January 2004, Published online: 23 April 2004 相似文献
2.
《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):831-835
e
+
e
- production was studied using the High Acceptance DiElectron Spectrometer (HADES). In pp collisions at 2.2GeV kinetic beam energy, the exclusive η production and the Dalitz decay η→γe
+
e
- have been reconstructed. The electromagnetic form factor of the latter decay was found to be in good agreement with the existing
theoretical predictions. In addition, an inclusive e
+
e
- invariant-mass spectrum from the 12C + 12C reaction at 2AGeV is presented and compared with a simplified thermal model. 相似文献
3.
C. Bl?chinger H. Fraas G. Moortgat-Pick W. Porod 《The European Physical Journal C - Particles and Fields》2002,24(2):297-310
We investigate selectron pair production and decay in e
-
e
-
scattering and e
+
e
-
annihilation with polarized beams taking into account neutralino mixing as well as initial state radiation and beamstrahlung
corrections. One of the main advantages of having both modes at disposal is their complementarity concerning the threshold
behavior of selectron pair production. In e
-
e
-
the cross sections at threshold for and increase proportional to the momentum of the selectron and in e
+
e
-
that for . Measurements at threshold with polarized beams can be used to determine the selectron masses precisely. Moreover we discuss how polarized electron and positron beams can be used to establish directly the weak quantum
numbers of the selectrons. We also use selectron pair production to determine the gaugino mass parameter M1. This is of particular interest for scenarios with non-universal gaugino masses at a high scale resulting in at the electroweak scale. Moreover, we consider also the case of non-vanishing selectron mixing and demonstrate that it leads
to a significant change in the phenomenology of selectrons.
Received: 30 January 2002 / Published online: 8 May 2002 相似文献
4.
M. N. Achasov K. I. Beloborodov A. V. Berdyugin A. G. Bogdanchikov A. V. Bozhenok A. D. Bukin D. A. Bukin T. V. Dimova V. P. Druzhinin V. B. Golubev A. A. Korol S. V. Koshuba E. V. Pakhtusova S. I. Serednyakov Yu. M. Shatunov V. A. Sidorov Z. K. Silagadze A. N. Skrinsky Yu. A. Tikhonov A. V. Vasiljev 《Journal of Experimental and Theoretical Physics》2006,103(3):380-384
The corrected cross section of the e
+
e
− → π+π− process measured in the spherical neutral detector experiment at the VEPP-2M e
+
e
− collider is presented. The update is necessary due to a flaw in the e
+
e
− → π+π− and e
+
e
− → μ+μ− Monte Carlo event generators used previously in data analysis.
The text was submitted by the authors in English. 相似文献
5.
C. Bini 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):446-450
The KLOE experiment at the Frascati e
+
e
- collider DAFNE has completed this year its data taking. An integrated luminosity of 2.7fb^-1 has been collected mostly at
the φ-resonance peak. A wide experimental program is in progress. The detection of φ radiative decays allows to study the properties of the lowest-mass scalar and pseudoscalar mesons and to obtain information
on their structure. The main results are reviewed together with the prospects for low-energy e
+
e
- physics at Frascati. 相似文献
6.
M. O. Distler 《The European physical journal. Special topics》2011,198(1):257-267
Few-body experiments at the Mainz Microtron were focused on a number of selected topics. Double-polarization experiments to
determine the neutron electric form factor Gen have been performed using both deuterium and polarized helium-3 targets. The structure of 3He has been studied in the reactions 3H e⃗ e(e⃗e,e′n) and 3H e⃗ e(e⃗e,e′p) with large (transversal) missing momenta and in quasi-elastic electron scattering. Electromagnetically induced two-nucleon
knockout has been investigated in order to study the role of correlated nucleon-nucleon motion in the nucleus. Measurements
of the (e,e′pn) reaction on 3He and 16O were performed for the first time. A triple-polarization experiment of type 3H e⃗ e(e⃗e,e′e⃗p⃗)d has been performed, where, in addition, the spin of the knocked out proton is analyzed. This measurement provides information
on the spin-dependent momentum distribution of proton-deuteron clusters in the 3He nucleus. Hence, by tagging the outgoing deuteron spin-polarized 3He might also serve as an effective polarized proton target for electron scattering experiments. Moreover, in inclusive 3,4He(e,e′) measurements at low momentum transfer, the effect of 3-body-forces has been studied. 相似文献
7.
Total (elastic+inelastic) cross sections fore
−-O,e
−-O2 ande
−-O3 scattering have been calculated at sample energies between 100 and 1000eV. The basice
−-O atom scattering amplitudes are obtained from the partial wave analysis with a complex optical potential. Thee
−-O2 ande
−-O3 cross-sections are obtained through the independent atom model. Oure
−-O2 cross-sections reproduce the experimental data quite well. Adequate comparisons are made in all the three cases. 相似文献
8.
We discuss the production, at high-energye
+
e
– linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair production and single production in association with ordinary fermions. Concentrating on new leptons, we use a model detector fore
+
e
– collisions at a center of mass energy of 500 GeV, to illustrate the discovery potential of the next linear colliders. 相似文献
9.
Electron cooling in three‐dimensional Dirac fermion systems at low temperature: Effect of screening 下载免费PDF全文
Hot electron cooling rate P, due to acoustic phonons, is investigated in three‐dimensional Dirac fermion systems at low temperature taking account of the screening of electron–acoustic phonon interaction. P is studied as a function of electron temperature Te and electron concentration ne. Screening is found to suppress P very significantly for about Te < 0.5 K and its effect reduces considerably for about Te > 1 K in Cd3As2. In Bloch–Grüneisen (BG) regime, for screened (unscreened) case the Te dependence is P ~ Te9(Te5) and the ne dependence gives P ~ ne–5/3 (ne–1/3). The Te dependence is characteristic of 3D phonons and ne dependence is characteristics of 3D Dirac fermions. The plot of P /Te4 vs. Te shows a maximum at temperature Tem which shifts to higher values for larger ne. Interestingly, the maximum is nearly same for different ne and Tem/ne1/3 being nearly constant. More importantly, we propose, the ne dependent measurements of P would provide a clearer signature to identify 3D Dirac semimetal phase. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
10.
S.V. Kukhlevsky A. Ritucci I.Z. Kozma J. Kaiser A. Shlyaptseva G. Tomassetti O. Samek 《等离子体物理论文集》2002,42(1):109-118
The gain saturation in the 46.9 nm line of the Ar+8 laser is analyzed using an atomic kinetics code. The dependence of the gain (G) on the electron kinetic temperature (Te) in the region (50 ‐150 eV) is calculated in the quasi steady‐state approximation for the different values of the electron density (Ne) and the plasma radius (rpl). The influence of radiat on trapping, ion random and mean velocities, Stark line broadening and refraction losses on the gain saturation is taken into consideration. For rpl = 150‐600 μm, the amplplication (G > 0 cm‐1) exists in the large temperature/density domain (Te = 60‐150 eV, Ne = 0.5‐10 × 1018 cm‐3). However, the value Gs ∼ 1.4 cm‐1 required for the gain saturation at the typical plasma length Lpl ∼ 15 cm is reached in the extremely narrow density regions at the high temperatures. The saturation is reached for rpl = 600 μm at Tse = 150 eV in the region Nse = 1.8‐2 × 1018 cm ‐3, for rpl = 300 μm at Tse = 125 eV and Nse = 2.5‐3 × 1018 cm‐3, and for rpl = 150 μm at Tse = 110 eV and Nse = 3‐4 × 1018 cm‐3. The broadest density region (Nse = 2 ‐8 × 1018 cm‐3) is predicted for the narrowest column (rpl = 150 μm) at the highest temperature (Tse = 150 eV). The operation in the broadest density region Nse, should make easier achievement of the gain saturation in the experiments. 相似文献
11.
Spectroscopic parameters and molecular constants of HI(X~1Σ~+),DI(X~1Σ~+) and TI(X~1Σ~+) isotope molecules 下载免费PDF全文
The potential energy curve (PEC) of HI(X1Σ+) molecule is studied using the complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration interaction approach at the correlation-consistent basis sets, aug-cc-pV6Z for H and aug-cc-pV5Z-pp for I atom. Using the PEC of HI(X1Σ+), the spectroscopic parameters of three isotopes, HI(X1Σ+), DI(X1Σ+) and TI(X1Σ+), are determined in the present work. For the HI(X1Σ+), the values of D0, De, Re, ωe, ωeχe, αe and Be are 3.1551 eV, 3.2958 eV, 0.16183 nm, 2290.60 cm-1, 40.0703 cm-1, 0.1699 cm-1 and 6.4373 cm-1, respectively; for the DI (X1Σ+), the values of D0, De, Re, ωe, ωeχe, αe and Be are 3.1965 eV, 3.2967 eV, 0.16183 nm, 1626.8 cm-1, 20.8581 cm-1, 0.0611 cm-1 and 3.2468 cm-1, respectively; for the TI (X1Σ+), the values of D0, De, Re, ωe, ωeχe, αe and Be are of 3.2144 eV, 3.2967 eV, 0.16183 nm, 1334.43 cm-1, 14.0765 cm-1, 0.0338 cm-1 and 2.1850 cm-1, respectively. These results accord well with the available experimental results. With the PEC of HI(X1Σ+) molecule obtained at present, a total of 19 vibrational states are predicted for the HI, 26 for the DI, and 32 for the TI, when the rotational quantum number J is equal to zero (J = 0). For each vibrational state, vibrational level G(?), inertial rotation constant B? and centrifugal distortion constant D? are determined when J = 0 for the first time, which are in excellent agreement with the experimental results. 相似文献
12.
C. P. Montoya S. Schadmand I. Diószegi D. J. Hofman P. H. Zhang P. Paul 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(4):371-375
The strength functions fore
+
e
– pair decay of the isoscalar and isovector giant monopole resonances in highly excited nuclei are derived and used in a statistical model calculation of thee
+
e
– pair energy spectrum from compound nuclear decay in110Sn following a fusion evaporation reaction. This result is then compared to thee
+
e
– spectrum derived from internal pair decay of the giant dipole and giant quadrupole resonances. The computation shows that the pair decay from the excited-state GDR dominates the pair spectrum over the region of all giant resonances, exceedingL=0 transitions by at least a factor of ten. We also compute the angular correlations betweene
+ ande
– for theL=0, L=1 andL=2 transitions and estimate their power to discriminate between the various multipolarities.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献
13.
《Physics letters. [Part B]》1998,440(3-4)
The mechanism of baryon-anti-baryon pair production in e+e− annihilation into hadrons has been studied using the TOPAZ detector at the TRISTAN e+e− collider at an average center-of-mass energy of 58 GeV. The distributions of various
correlations were compared with two prominent models: the cluster-fragmentation model and the string-fragmentation model. We rejected the cluster-fragmentation model at the 90% C.L. Furthermore, in the context of the string-fragmentation model, we favor the “popcorn” model, rejecting the “diquark” model, where a diquark is considered to be a fundamental entity, at the 95% C.L. 相似文献
14.
The analysis of the lepton angular distribution at LEP is reviewed and the specific concerns in the case ofe
+
e
– final state are singled out. Studies of the physical information contained in thee
+
e
– angular distribution are shown to justify the need for a new approach. Two different solutions that enable the complete use of the angular distribution information for the extraction of theZ parameters are presented. We show that these approaches have accuracies well above the future experimental needs. 相似文献
15.
Accurate potential energy function and spectroscopic study of the X^2∑+, A^2П and B^2∑+ states of the CP radical 下载免费PDF全文
This paper calculates the equilibrium internuclear separations, the harmonic frequencies and the potential energy curves of the X^2∑+, A^2П and B^2∑+ states of the CP radical by the highly accurate valence internally contracted multireference configuration interaction method with correlation-consistent basis sets (aug-cc-pV6Z for C atom and aug-cc-pVQZ for P atom). The potential energy curves are all fitted with the analytic potential energy function by the least-square fitting. Employing the analytic potential energy function, we determine the spectroscopic constants (Be, αe and ωeχe) of these states. For the X2∑+ state, the obtained values of De, Be, αe, ωeχe, Re and ωe are 5.4831 eV, 0.792119 cm-1, 0.005521 cm-1, 6.89653 cm-1, 0.15683 nm, 12535.11 cm-1, respectively. For the A2H state, the present values of De, Be,αe, ωeχe, Re and We are 4.586 eV, 0.703333 cm-1, 0.005458 cm-1, 6.03398 cm-1, 0.16613 nm, 1057.89 cm-1, respectively. For the B2E+ state, the present values of De, Be, αe, ωeχe, Re and We are 3.506 eV, 0.677561 cm-1, 0.00603298 cm-1, 5.68809 cm-1, 0.1696 nm, 822.554 cm-1, respectively. For these states, the vibrational states with the rotational quantum number J equals zero (J = 0) are studied by solving the radial nuclear Schr6dinger equation using the Numerov method. For each vibrational state, the vibrational level, the classical turning points, the rotational inertial and the centrifugal distortion constants are calculated. Comparison is made with recent theoretical and experimental results. 相似文献
16.
V. I. Telnov 《Pramana》2007,69(6):1177-1179
One of the interaction regions at the linear colliders should be compatible both with e
+
e
− and γγ, γe modes of operation. In this paper, the differences in requirements and possible design solutions are discussed.
相似文献
17.
Molecular constants of LiCl(X~1Σ~+) and elastic collisions of two ground-state Cl and Li atoms at low and ultralow temperatures 下载免费PDF全文
Interaction potentials for LiCl(X 1 Σ +) are constructed by the highly accurate valence internally contracted mul-tireference configuration interaction in combination with a number of large correlation-consistent basis sets,which are used to determine the spectroscopic parameters (D 0,D e,R e,ω e,ω e χ e,B e and α e).The potentials obtained at the basis sets,i.e.,aug-cc-pV5Z-JKFI for Cl and cc-pV5Z for Li,are selected to study the elastic collision properties of Li and Cl atoms at the impact energies from 1.0×10 12 to 1.0×10 4 a.u.The derived total elastic cross sections are very large and almost constant at ultralow temperatures,and their shapes are mainly dominated by the s-partial wave at very low impact energies.Only one shape resonance can be found in the total elastic cross sections over the present collision energy regime,which is rather strong and obviously broadened by the overlap contributions of the abundant resonances coming from various partial waves.Abundant resonances exist for the elastic partial-wave cross sections until l=22 partial waves.The vibrational manifolds of the LiCl(X 1 Σ +) molecule,which are predicted at the present level of theory and the basis sets cc-pV5Z for Li and the aug-cc-pV5Z-JKFI for Cl,should achieve much high accuracy due to the employment of the large correlation-consistent basis sets. 相似文献
18.
We review high-energy scattering processes that are sensitive to the hadronic structure of the photon, describing theoretical
predictions as well as recent experimental results. These processes include deep-inelastic electron-photon scattering ate
+
e
− colliders; and the production of jets, heavy quarks and isolated photons in the collision of real photons ate
+
e
− colliders, as well as in photon-photon collisions atep colliders. We also comment on minijet based calculations of totalγp andγγ cross-sections, and discuss the possibility that future lineare
+
e
− colliders might produce very large photon fluxes due to the beamstrahlung phenomenon; in the most extreme cases, we predict
more than one hadronicγγ event to occur at every bunch crossing. 相似文献
19.
Theoretical investigations of spectroscopic parameters and molecular constants for electronic ground state of Cl2 and its isotopes 下载免费PDF全文
The potential energy curve of the Cl 2(X1Σg+) is investigated by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the largest correlation-consistent basis set, aug-cc-pV6Z, in the valence range. The theoretical spectroscopic parameters and the molecular constants of three isotopes, 35Cl2, 35Cl37Cl and 37Cl2, are studied. For the 35Cl2 (X1Σg+), the values of D0 , De , Re , ωe , ωeχe , αe and Be are obtained to be 2.3921 eV, 2.4264 eV, 0.19939 nm, 555.13 cm-1 , 2.6772 cm-1 , 0.001481 cm-1 and 0.24225 cm-1 , respectively. For the 35Cl37Cl(X1Σg+), the values of D0 , De , Re , ωe , ωeχe , αe and Be are calculated to be 2.3918 eV, 2.4257 eV, 0.19939 nm, 547.68 cm-1 , 2.6234 cm-1 , 0.00140 cm-1 and 0.23572 cm-1 , respectively. And for the 37C2 (X1Σg+), the values of D0 , De , Re , ωe , ωeχe , αe and Be are obtained to be 2.3923 eV, 2.4257 eV, 0.19939 nm, 540.06 cm-1 , 2.5556 cm-1 , 0.00139 cm-1 and 0.22919 cm-1 , respectively. These spectroscopic results are in good agreement with the available experimental data. With the potential of Cl2 molecule determined at the MRCI/aug-cc-pV6Z level of theory, the total of 59 vibrational states is predicted for each isotope when the rotational quantum number J equals zero (J = 0). The theoretical vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J = 0, which are in excellent accordance with the available experimental findings. 相似文献
20.
Aseshkrishna Datta A. Djouadi M. Mühlleitner 《The European Physical Journal C - Particles and Fields》2002,25(4):539-551
We analyze the associated production at future high-energy e
+
e
-
colliders, of first generation sleptons with neutralinos and charginos in the modes e
+
e
-
and , in the framework of the minimal supersymmetric extension of the standard model. We show that the production rates, in particular
for associated production of right-handed selectrons and the lightest neutralino which in general is the first accessible
kinematically, can be much larger than the corresponding ones for second and third generation scalar leptons and for scalar
quarks. With the high luminosities expected at these colliders, the detection of first generation sleptons with masses significantly
above the kinematical two-body threshold, , is thus possible in favorable regions of the parameter space.
Received: 27 June 2002 / Published online: 20 September 2002 相似文献