Mirage in the Sky: Non-thermal Dark Matter, Gravitino Problem, and Cosmic Ray Anomalies

Recent anomalies in cosmic rays could be due to dark matter annihilation in our galaxy. In order to get the required large cross-section to explain the data while still obtaining the right relic density, we rely on a non standard thermal history between dark matter freeze-out and Big-Bang Nucleosynthesis (BBN). We show that through a reheating phase from the decay of a heavy moduli or even the gravitino, we can produce the right relic density of dark matter if its self-annihilation cross-section is large enough. In addition to fitting the recent data, this scenario solves the cosmological moduli and gravitino problems. We illustrate this mechanism with a specific example in the context of U(1)_{B-L} extended MSSM where supersymmetry is broken via mirage mediation. These string motivated models naturally contain heavy moduli decaying to the gravitino, whose subsequent decay to the LSP can reheat the universe at a low temperature. The right-handed sneutrino and the B-L gaugino can both be viable dark matter candidates with large cross-section. They are leptophilic because of B-L charges. We also show that it is possible to distinguish the non-thermal from the thermal scenario (using Sommerfeld enhancement) in direct detection experiments for certain regions of parameter space.Comment: 11 pages, 4 figure

Low-scale Inflation and Supersymmetry Breaking in Racetrack Models

In many moduli stabilization schemes in string theory, the scale of inflation appears to be of the same order as the scale of supersymmetry breaking. For low-scale supersymmetry breaking, therefore, the scale of inflation should also be low, unless this correlation is avoided in specific models. We explore such a low-scale inflationary scenario in a racetrack model with a single modulus in type IIB string theory. Inflation occurs near a point of inflection in the K\"ahler modulus potential. Obtaining acceptable cosmological density perturbations leads to the introduction of magnetized D7-branes sourcing non-perturbative superpotentials. The gravitino mass, m_{3/2}, is chosen to be around 30 TeV, so that gravitinos that are produced in the inflaton decay do not affect big-bang nucleosynthesis. Supersymmetry is communicated to the visible sector by a mixture of anomaly and modulus mediation. We find that the two sources contribute equally to the gaugino masses, while scalar masses are decided mainly by anomaly contribution. This happens as a result of the low scale of inflation and can be probed at the LHC.Comment: 10 pages, 3 Figures, Late

Attractors, Universality and Inflation

Studies of the initial conditions for inflation have conflicting predictions from exponential suppression to inevitability. At the level of phase space, this conflict arises from the competing intuitions of CPT invariance and thermodynamics. After reviewing this conflict, we enlarge the ensemble beyond phase space to include scalar potential data. We show how this leads to an important contribution from inflection point inflation, enhancing the likelihood of inflation to an inverse cubic power law. In the process, we emphasize the attractor dynamics of the gravity-scalar system and the existence of universality classes from inflection point inflation. Finally, we comment on the predictivity of inflation in light of these results.Comment: 32 pages, 8 figures. Typos and figures fixe

Successful Supersymmetric Dark Matter with Thermal Over/Under-Abundance from Late Decay of a Visible Sector Scalar

We present an explicit model where the decay of an R-parity even scalar $S$ with ${\cal O}({\rm TeV})$ mass is the origin of non-thermal dark matter. The correct relic abundance can be produced for both large and small annihilation rates in accordance with the Fermi constraints on the annihilation cross-section. This scenario has advantages over that of non-thermal dark matter from modulus decay. First, branching ratio for production of R-parity odd particles can be made quite small by a combination of $S$ couplings to matter fields and kinematic suppression, enabling us to obtain the observed dark matter relic density in cases of thermal underproduction as well as overproduction. Second, gravitino production is naturally suppressed by the virtue of decaying scalar belonging to the visible sector. The decaying scalar $S$ can also successfully generate baryon asymmetry of the universe, and may provide an explanation for the baryon-dark matter coincidence puzzle.Comment: 9 pages, 3 figure

Holomorphic Bisectional Curvatures, Supersymmetry Breaking, and Affleck-Dine Baryogenesis

Working in $D=4, N=1$ supergravity, we utilize relations between holomorphic sectional and bisectional curvatures of Kahler manifolds to constrain Affleck-Dine baryogenesis. We show the following No-Go result: Affleck-Dine baryogenesis cannot be performed if the holomorphic sectional curvature at the origin is isotropic in tangent space; as a special case, this rules out spaces of constant holomorphic sectional curvature (defined in the above sense) and in particular maximally symmetric coset spaces. We also investigate scenarios where inflationary supersymmetry breaking is identified with the supersymmetry breaking responsible for mass splitting in the visible sector, using conditions of sequestering to constrain manifolds where inflation can be performed.Comment: 9 page

Correlation between Dark Matter and Dark Radiation in String Compactifications

Reheating in string compactifications is generically driven by the decay of the lightest modulus which produces Standard Model particles, dark matter and light hidden sector degrees of freedom that behave as dark radiation. This common origin allows us to find an interesting correlation between dark matter and dark radiation. By combining present upper bounds on the effective number of neutrino species N_eff with lower bounds on the reheating temperature as a function of the dark matter mass m_DM from Fermi data, we obtain strong constraints on the (N_eff,m_DM)-plane. Most of the allowed region in this plane corresponds to non-thermal scenarios with Higgsino-like dark matter. Thermal dark matter can be allowed only if N_eff tends to its Standard Model value. We show that the above situation is realised in models with perturbative moduli stabilisation where the production of dark radiation is unavoidable since bulk closed string axions remain light and do not get eaten up by anomalous U(1)s.Comment: 9 pages, 3 figure

Non-thermal Dark Matter in String Compactifications

Non-thermal cosmological histories are capable of greatly increasing the available parameter space of different particle physics dark matter (DM) models and are well-motivated by the ubiquity of late-decaying gravitationally coupled scalars in UV theories like string theory. A non-thermal DM model is presented in the context of LARGE Volume Scenarios in type IIB string theory. The model is capable of addressing both the moduli-induced gravitino problem as well as the problem of overproduction of axionic dark radiation and/or DM. We show that the right abundance of neutralino DM can be obtained in both thermal under and overproduction cases for DM masses between O(GeV) to O(TeV). In the latter case the contribution of the QCD axion to the relic density is totally negligible, while in the former case it can be comparable to that of the neutralino thus resulting in a multi-component DM scenario.Comment: 7 page

Searching for Top Squarks at the LHC in Fully Hadronic Final State

We pursue a scenario where the lighter top squark (stop) mass is accessible for the Large Hadron Collider (LHC) in the near future, while gluinos and first two generation squarks are heavier. At $\sqrt{s} = 8$ TeV, we investigate the identification of stops which decay predominantly into a top quark and the stable lightest supersymmetric particle. We use a simple kinematical variable, $M3$, to reconstruct two top quarks which are pair-produced from the stops, in the fully hadronic channel. The dominant Standard Model (SM) background for this signal stems from $t\bar t$ plus jets, with one top quark decaying into $bl\nu$, where the lepton is undetected and the $\nu$ produces missing transverse momentum. The lepton identification efficiency is thus crucial in order to estimate the background correctly. We identify kinematical variables to reduce the SM background. We find that it is possible to achieve signal and background cross-section at similar levels for stop masses around $350 - 500$ GeV for a neutralino mass of 100 GeV.Comment: 7 pages, 6 figure

Role of NGOs in Good Governance

Voluntary organisations play a vital role in shaping and implementation of participatory democracy. The main role of NGOs has been in enforcement provision. Their "gap-flling‟ role and independence from government has allowed them to implement innovative approaches that can serve as models for government and the public enforcement system. In this sense, NGOs should continue doing what they already do best in order to become a useful laboratory for government. Mainstreaming such successful innovations in cooperation with government thus becomes an enforcement of human rights process par excellence; going beyond the individual and community level, this type of scaling up can become part of enforcement of human rights sector reform, involving all levels and actors, and incorporating NGOs as policy-partners and advisors. NGOs can become acknowledged innovators in the public interest, with a constant eye on adoption by bigger and more powerful actors and on enhancing the capacity of claimants

A Review of Corporate Sustainability Reporting: Global and National scenario

Global concerns of climate change, poverty, human rights violations, and legal compliances have entailed corporate to pay attention towards social and environmental issues. Company‟s responsibility towards environment and social are reflected in their sustainability report (SR). The current sustainability reporting movement emerged in the US during the late 1980s, in response to the US 1987 Superfund Amendments and Reauthorization Act. Sustainability reporting gave multiple benefit of improvement in financial performance, stakeholder relationships, risk management, investor relationships, and Identification of new markets. However, the progress of sustainability reporting in India was slow, but a significant and sound start has been made. Adopting the principles of sustainability companies could make both comparative as well as competitive advantage over other. At present, there are good institutional setup and skilled human resource in India for developing Sustainability Reports. In this regard, there are no excuses for Indian businesses to not include them in their portfolio. With this Indian corporate show great interest in sustainability and sound growth has already been observed. Reporting practices will make companies to long term profitable, ethical, brand image and resourceful. It is proposed that a good Sustainability Report should give a holistic view of business and help the organization to design its strategy and prepare it suitably for different kinds of business cycles