14074616
Classification of supersymmetric flux vacua in M-theory
Abstract We present a comprehensive classification of supersymmetric vacua of M-theory compactification on seven-dimensional manifolds with general four-form fluxes. We analyze the cases where the resulting four-dimensional vacua have N = 1 , 2 , 3 , 4 supersymmetry and the internal space allows for SU ( 2 ) , SU ( 3 ) or G 2 structures. In particular, we find for N = 2 supersymmetry, that the external space–time is Minkowski and the base manifold of the internal space is conformally Kahler for SU ( 2 ) structures, while for SU ( 3 ) structures the internal space has to be Einstein–Sasaki and no internal fluxes are allowed. Moreover, we provide a new vacuum with N = 1 supersymmetry and SU ( 3 ) structure, where all fluxes are non-zero and the first order differential equations are solved.
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.
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.
119264713
Measuring Di-Higgs Physics via the $t \bar t hh \to t \bar t b \bar bb\bar b$ Channel
The measurement of di-Higgs physics can provide crucial information on electroweak phase transition in the early Universe and significant clues on new physics coupling with the Higgs field directly. This measurement has been suggested to be pursued mainly via the $pp \to hh$ production. In this letter, we propose a new strategy to do that, i.e., via the $pp \to t \bar t hh $ production. Because of its positive correlation with the rescaled tri-Higgs coupling $\frac{\lambda}{\lambda_{\rm SM}}$ (in comparison to a negative one for the $pp \to hh$ production) in the neighborhood of $\frac{\lambda}{\lambda_{\rm SM}} \sim 1$, the $pp \to t\bar t hh$ production complements the $pp \to hh$ one in measuring di-Higgs physics, particularly for $\frac{\lambda}{\lambda_{\rm SM}}>1$, at both the High Luminosity LHC (HL-LHC) and a next-generation $pp$-collider. As an illustration, we work on the process $pp\to t\bar thh \to t\bar t b\bar b b\bar b$. We show that a statistical significance of $> 2.0 \sigma$ at the HL-LHC, comparable to that of the $pp \to hh \to b\bar b \gamma\gamma$ channel, and a statistical significance of $\sim 5 \sigma$ at a 100 TeV $pp$-collider, with 3000 fb$^{-1}$ of data, are achievable in searching for the di-Higgs production with $\frac{\lambda}{\lambda_{\rm SM}} = 1$.
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.
6496614
Response of a 0.25 μm thin-film silicon-on-sapphire CMOS technology to total ionizing dose
The radiation response of a 0.25 μm silicon-on-sapphire CMOS technology is characterized at the transistor and circuit levels utilizing both standard and enclosed layout devices. The threshold-voltage shift is less than 170 mV and the leakage-current increase is less than 1 nA for individual standard-layout nMOSFET and pMOSFET devices at a total dose of 100 krad(SiO2). The increase in power supply current at the circuit level was less than 5%, consistent with the small change in off-state transistor leakage current. The technology exhibits good characteristics for use in the electronics of the ATLAS experiment at the Large Hadron Collider.
15092713
A serializer ASIC for high speed data transmission in cryogenic and HiRel environment
A high speed 16:1 serializer ASIC has been developed using a commercial 0.25 μm silicon-on-sapphire CMOS technology. At room temperature the ASIC operates from 4.0 to 5.7 Gbps with power consumption of 463 mW. The total jitter is 62 ps at the bit error rate of 10−12 at 5 Gbps. A 200-MeV proton beam test indicates that the ASIC is suitable for high energy physics applications. A liquid nitrogen temperature test indicates that the ASIC may be used at cryogenic temperature applications. The reliability of the serializer at liquid nitrogen temperature is to be studied. A 6-lane serializer array with 10 Gbps/lane with redundancy capability is under development.
118568439
Active inductor shunt peaking in high-speed VCSEL driver design
An all transistor active inductor shunt peaking structure has been used in a prototype of 8-Gbps highspeed VCSEL driver which is designed for the optical link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated in a commercial 0.25-μm Silicon-on-Sapphire (SoS) CMOS process for radiation tolerant purpose. The all transistor active inductor shunt peaking is used to overcome the bandwidth limitation from the CMOS process. The peaking structure has the same peaking effect as the passive one, but takes a small area, does not need linear resistors and can overcome the process variation by adjust the peaking strength via an external control. The design has been tapped out, and the prototype has been proofed by the preliminary electrical test results and bit error ratio test results. The driver achieves 8-Gbps data rate as simulated with the peaking. We present the all transistor active inductor shunt peaking structure, simulation and test results in this paper.
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%.