119444679
Supersymmetric standard models, flux compactification and moduli stabilization
Abstract Based on the T-dual constructions of supersymmetric intersecting D6-models on Z 2 × Z 2 orientifolds, whose electroweak sector is parallel with the orientifold planes with Sp ( 2 f ) L × Sp ( 2 f ) R gauge symmetry [ hep-th/0407178 ], we derive and classify standard model-like vacua with RR and NSNS fluxes, which stabilize toroidal complex structure moduli and the dilaton. We find consistent four-family ( f = 4 ) and two-family ( f = 2 ) models with one- and two-units of the quantized flux, respectively. Such models typically possess additional gauge group factors with negative beta functions and may lead, via gaugino condensation, to stabilization of toroidal Kahler moduli. These models have chiral exotics.
119074364
Post-ACME2013 CP-violation in Higgs Physics and Electroweak Baryogenesis
We present a class of cancellation mechanisms to suppress the total contributions of Barr-Zee diagrams to the electron electric dipole moment (eEDM). This class of mechanisms are of particular significance after the new eEDM upper limit, which strongly constrains the allowed magnitude of CP-violation in Higgs couplings and hence the feasibility of electroweak baryogenesis (EWBG), were released by the ACME collaboration in 2013. We point out: if both the CP-odd Higgs-photonphoton (Z boson) and the CP-odd Higgs-electron-positron couplings are turned on, a cancellation may occur either between the contributions of a CP-mixing Higgs boson, with the other Higgs bosons being decoupled, or between the contributions of a CP-even and a CP-odd Higgs bosons. With the assistance of the cancellation mechanisms, a large CP-phase in Higgs couplings with viable electroweak baryogenesis (EWBG) is still allowed. The reopened parameter regions would be probed by the future neutron, mercury EDM measurements, and direct measurements of Higgs CP-properties at the LHC and future colliders.
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.
44596378
Unraveling the physics behind modified Higgs couplings: LHC versus a Higgs factory
Strongly modified $h\ensuremath{\gamma}\ensuremath{\gamma}$ and $hgg$ couplings indicate new electroweak and color mediators, respectively, with a light mass and a significant coupling to the Higgs boson. We point out the Higgs boson could have a significant decay width into the mediators. This represents one new class of exotic Higgs decay possibilities: off-shell exotic Higgs decays. We then propose uncovering the hidden new physics through such exotic decays. A great advantage of this strategy is that we can directly probe the couplings between the Higgs boson and the mediators, which is hard to achieve by using other methods. Focusing on the electroweak mediators, we study a simplified model using as an example final states with tau leptons and neutrinos. Because one of the mediators is off shell and its decay products are extremely soft, it is challenging to make a discovery at the Large Hadron Collider. A Higgs factory such as the International Linear Collider, however, could serve as a discovery machine for such exotic Higgs decays even in an early stage.
118316245
Exotic Higgs Decay h to 2a at the International Linear Collider: a Snowmass White Paper
A Higgs factory like the International Linear Collider (ILC) can play a significant role in searching for exotic decays of Higgs bosons. As an illustration, we investigate the ILC sensitivity for the decay topology $h\to a_1 a_1 \to \tau\bar \tau\tau \bar \tau$ in the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM). Here $h$ can be either Standard-Model-like or non-standard, and $a_{1}$ is the lightest CP-odd Higgs boson. We also compare results to expectations for this channel at the LHC.
33634938
Standardlike models as type IIB flux vacua
We construct new semirealistic type IIB flux vacua on ${Z}_{2}\ifmmode\times\else\texttimes\fi{}{Z}_{2}$ orientifolds with three- and four-standard model families and up to three units of quantized flux. The open string sector is comprised of magnetized D-branes and is T-dual to supersymmetric intersecting D6-brane constructions. The standard model sector contains magnetized D9-branes with negative D3-brane charge contribution. There are large classes of such models and we present explicit constructions for representative ones. In addition to models with one and two units of quantized flux, we also construct the first three- and four-family standard-like models with supersymmetric fluxes, i.e. comprising three units of quantized flux. Supergravity fluxes are due to the self-dual Neveu-Schwarz-Neveu-Schwarz and Ramond-Ramond three-form field strength and they fix the toroidal complex structure moduli and the dilaton. The supersymmetry conditions for the D-brane sector fix in some models all three toroidal K\"ahler moduli. We also provide examples where toroidal K\"ahler moduli are fixed by strong gauge dynamics on the ``hidden sector'' D7-brane. Most of the models possess Higgs doublet pairs with Yukawa couplings that can generate masses for quarks and leptons. The models have (mainly right-) chiral exotics.
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.
9969479
Pseudo-goldstino and electroweakinos via VBF processes at LHC
A bstractThe multi-sector SUSY breaking predicts pseudo-goldstino which can couple to the visible sector more strongly than the ordinary gravitino and thus induce the decays of the lightest neutralino and chargino (collectively called electroweakinos) inside the detector. In this note we study the electroweakino pair productions via VBF processes followed by decays to pseudo-goldstino at the LHC. Our Monte Carlo simulations show that at the 14 TeV LHC with 3000 fb−1 luminosity the dominant production channel pp → χ1∓χ10jj can have a statistical significance above 2σ while other production channels are not accessible.
111231338
Update on the high speed serializer ASIC development for ATLAS Liquid Argon calorimeter upgrade
We have been developing a serializer application-specific integrated circuit (ASIC) based on a commercial 0.25-μm silicon-on-sapphire (SOS) CMOS technology for the ATLAS liquid argon calorimeter front-end electronics upgrade. The first prototype, a 5 Gbps 16:1 serializer has been designed, fabricated, and tested in lab environment and in a 200 MeV proton beam. The test results indicate that the first prototype meets the design goals. The second prototype, a double-lane, 8 Gbps per lane serializer is under development. The post-layout simulation indicates that 8 Gbps is achievable. In this paper we present the design and the test results of the first prototype and the design and status of the second prototype.
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.