118430959
Quark angular momentum in a spectator model
Abstract We investigate the quark angular momentum in a model with the nucleon being a quark and a spectator. Both scalar and axial-vector spectators are included. We perform the calculations in the light-cone formalism where the parton concept is well defined. We calculate the quark helicity and canonical orbital angular momentum. Then we calculate the gravitational form factors which are often related to the kinetic angular momentums, and find that even in a no gauge field model we cannot identify the canonical angular momentums with half the sum of gravitational form factors. In addition, we examine the model relation between the orbital angular momentum and pretzelosity, and find it is violated in the axial-vector case.
119232315
Quark orbital motions from Wigner distributions
We investigate quark Wigner distributions in a light-cone spectator model. Both the scalar and the axial-vector spectators are included. The light-cone wave functions are derived from effective quark-spectator-nucleon vertex and then generalized by adjusting the power of energy denominators. The gauge link is taken into account by introducing relative phases to the light-cone amplitudes, and the phases are estimated from one gluon exchange interactions. The mixing distributions, which describe the correlation between transverse coordinate and transverse momentum and represent quark orbital motions, are calculated from the Wigner distributions. We find both $u$ quark and $d$ quark have positive orbital angular momentum in a polarized proton at small $x$ region, but a sign change is observed at large $x$ region for the $d$ quark. Besides, some model relations between Wigner distributions with different polarization configurations are found.
12407511
A 4.9-GHz low power, low jitter, LC phase locked loop
This paper presents a low power, low jitter LC phase locked loop (PLL) which has been designed and fabricated in a commercial 0.25-μm Silicon-on-Sapphire CMOS technology. Random jitter and deterministic jitter of the PLL are 1.3 ps and 7.5 ps, respectively. The measured tuning range, from 4.6 to 5.0 GHz, is narrower than the expected one, from 3.8 to 5.0 GHz. The narrow tuning range issue has been investigated and traced to the first stage of the divider chain. The power consumption at the central frequency is 111 mW.
118915813
Supersymmetric Pati–Salam models from intersecting D6-branes: a road to the Standard Model
Abstract We provide a systematic construction of three-family N = 1 supersymmetric Pati–Salam models from Type IIA orientifolds on T 6 / ( Z 2 × Z 2 ) with intersecting D6-branes. All the gauge symmetry factors SU ( 4 ) C × SU ( 2 ) L × SU ( 2 ) R arise from the stacks of D6-branes with U ( n ) gauge symmetries, while the “hidden sector” is specified by USp ( n ) branes, parallel with the orientifold planes or their Z 2 images. The Pati–Salam gauge symmetry can be broken down to the SU ( 3 ) C × SU ( 2 ) L × U ( 1 ) B − L × U ( 1 ) I 3 R via D6-brane splittings, and further down to the Standard Model via D- and F-flatness preserving Higgs mechanism from massless open string states in a N = 2 subsector. The models also possess at least two confining hidden gauge sectors, where gaugino condensation can in turn trigger supersymmetry breaking and (some) moduli stabilization. The systematic search yields 11 inequivalent models: 8 models with less than 9 Standard Model Higgs doublet-pairs and 1 model with only 2 Standard Model Higgs doublet-pairs, 2 models possess at the string scale the gauge coupling unification of SU ( 2 ) L and SU ( 2 ) R , and all the models possess additional exotic matters. We also make preliminary comments on phenomenological implications of these models.
118573832
Neutrino Flavor Ratio on Earth and at Astrophysical Sources
We present the reconstruction of neutrino flavor ratios at astrophysical sources. For distinguishing the pion source and the muon-damped source to the 3$\sigma$ level, the neutrino flux ratios, $R\equiv\phi(\nu_\mu)/(\phi(\nu_e)+\phi(\nu_\tau))$ and $S\equiv\phi(\nu_e)/\phi(\nu_\tau)$, need to be measured in accuracies better than 10%.
109713979
Link model simulation and power penalty specification of the versatile link systems
This paper presents simulation and experimental studies of optical power penalties on the Versatile Link, a common R&D project on high-speed optical link for SLHC experiments. The 10 Gigabit Ethernet (10GbE) link model is examined and conservative link power penalties are predicted. We conduct parameter sensitivity analyses and find that the transmitter characteristics affect the link power penalties most. Power penalty differences of multi-mode and single-mode commerical transceiver modules over different fiber lengths are tested to be within the simulation limits. The optical power budgets are then proposed for different Versatile Link variants.
17752635
Quasi-supersymmetric G3 unification from intersecting D6-branes on Type IIA orientifolds
Abstract We construct three quasi-supersymmetric G 3 GUT models with S 3 symmetry and gauge coupling unification from intersecting D6-branes on Type IIA orientifolds. The Standard Model fermions and Higgs doublets can be embedded into the bifundamental representations in these models, and there is no any other unnecessary massless representation. Especially in Model I with gauge group U (4) 3 , we just have three-family SM fermions and three pairs of Higgs particles. The G 3 gauge symmetry in these models can be broken down to the Standard Model gauge symmetry by introducing light open string states. And 1 TeV scale supersymmetry breaking soft masses imply the reasonable intermediate string scale.