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.
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.
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.
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.
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.
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.
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.
55746504
The versatile link, a common project for super-LHC
A common project to develop a bi-directional, radiation tolerant, high speed (4.8 Gb/s) optical link for future high energy physics experiments is described. Due to be completed in 2012, it targets the upgrade programs of detectors installed at CERN's Large Hadron Collider (LHC). The development of radiation and magnetic field tolerant opto-electronic devices, fibre and connectors is described. Both Single-Mode and Multi-Mode versions of the system operating respectively at 850 nm and 1310 nm wavelength are proposed. First results at component and system level are presented, based mostly on commercially available devices.
14992394
An Optical Demo-Link for ATLAS Inner Detector Readout Upgrade
The GOL ASIC is a serializer chip developed by CERN based on a 0.25 μm CMOS technology [1]. The GOL operates with two data rates: 800 Mbps and 1.6 Gbps. This ASIC has been evaluated with radiation tolerance requirement for the ATLAS Inner Detector upgrade for the SLHC 1 . A demo-link has been designed and constructed to read out silicon detectors in the test staves through fiber optics. Through this demo-link we plan to study system issues in a giga-bit optical link. This concept will be extended to future serializer ASICs like the GBTx and the LOC when they become available. Experience gained from these demolinks will help us design and build a reliable optical readout system for new ATLAS Inner Detector readout.
118803187
Angular momentum decomposition from a QED example
We investigate the angular momentum decomposition with a quantum electrodynamics example to clarify the proton spin decomposition debates. We adopt the light-front formalism where the parton model is well defined. We prove that the sum of fermion and boson angular momenta is equal to half the sum of the two gravitational form factors $A(0)$ and $B(0)$, as is well known. However, the suggestion to make a separation of the above relation into the fermion and boson pieces, as a way to measure the orbital angular momentum of fermions or bosons, respectively, is not justified from our explicit calculation.