Lepton Flavour Violation in Unparticle Physics

Recently H. Georgi has introduced an unparticle \unpart in order to describe the low energy physics of a nontrivial scale invariant sector of an effective theory. In this work we have explored the phenomenology of an unparticle using the lepton flavour violating decay $\mu^{-}\to e^{-} e^{+} e^{-}$, and found that the branching ratio of this decay is strongly dependent on the scaling dimension.Comment: 7 pages, 3 figures; typographical errors corrected and references added in version

Graviton emission from a higher-dimensional black hole

We discuss the graviton absorption probability (greybody factor) and the cross-section of a higher-dimensional Schwarzschild black hole (BH). We are motivated by the suggestion that a great many BHs may be produced at the LHC and bearing this fact in mind, for simplicity, we shall investigate the intermediate energy regime for a static Schwarzschild BH. That is, for $(2M)^{1/(n-1)}\omega\sim 1$, where $M$ is the mass of the black hole and $\omega$ is the energy of the emitted gravitons in $(2+n)$-dimensions. To find easily tractable solutions we work in the limit $l \gg 1$, where $l$ is the angular momentum quantum number of the graviton.Comment: 10 pages, 8 figures, references added, typos corrected. Graviton degeneracy factor included; main results remain unchange

Neutrino lensing and modification of Newtonian gravity at large distances

The nature of the modification to neutrino lensing from galaxies, as caused by possible modifications to Newtonian gravity at large distances, is studied.Comment: 6 pages, 1 figur

Lepton polarization in B→K1ℓ+ℓ−B \to K_1 \ell^+ \ell^- Decays

We study the single and double lepton polarization asymmetries in the semileptonic $B$ meson decays $B \to K_1 (1270) \ell^+ \ell^-$ $\ell \equiv e$, $\mu$, $\tau$), where the strange $P$-wave meson, $K_1(1270)$, is the mixtures of the $K_{1A}$ and $K_{1B}$, which are the $1^3P_1$ and $1^1P_1$ states, respectively. The lepton polarization asymmetries show relatively strong dependency in the various region of dileptonic invariant mass. The lepton polarization asymmetries can also be used for determining the $K_1(1270)$--$K_1(1400)$ mixing angle, $\theta_{K_1}$ and new physics effects. Furthermore, it is shown that these asymmetries in $B\to K_1(1270)\ell^+\ell^-$ decay compared with those of $B\to K^*\ell^+\ell^-$ decay are more sensitive to the dileptonic invariant mass

Natural supersymmetry and unification in five dimensions

We explore unification and natural supersymmetry in a five dimensional extension of the standard model in which the extra dimension may be large, of the order of 1–10 TeV. Power law running generates a TeV scale At term allowing for the observed 125 GeV Higgs and allowing for stop masses below 2 TeV, compatible with a natural SUSY spectrum. We supply the full one-loop RGEs for various models and use metastability to give a prediction that the gluino mass should be lighter than 3.5 TeV for At ≥ −2.5 TeV, for such a compactification scale, with brane localised 3rd generation matter. We also discuss models in which only the 1st and 2nd generation of matter fields are located in the bulk. We also look at electroweak symmetry breaking in these models.NCS201

Learning from generations of sustainability concepts

Background: For decades, scientists have attempted to provide a sustainable development framework that integrates goals of environmental protection and human development. The Planetary Boundaries concept (PBc)—a framework to guide sustainable development—juxtaposes a 'safe operating space for humanity' and 'planetary boundaries', to achieve a goal that decades of research have yet to meet. We here investigate if PBc is sufficiently different to previous sustainability concepts to have the intended impact, and map how future sustainability concept developments might make a difference. Design: We build a genealogy of the research that is cited in and informs PBc. We analyze this genealogy with the support of two seminal and a new consumer-resource models, that provide simple and analytically tractable analogies to human-environment relationships. These models bring together environmental limits, minimum requirements for populations and relationships between resource-limited and waste-limited environments. Results: PBc is based on coherent knowledge about sustainability that has been in place in scientific and policy contexts since the 1980s. PBc represents the ultimate framing of limits to the use of the environment, as limits not to single resources, but to Holocene-like Earth system dynamics. Though seldom emphasized, the crux of the limits to sustainable environmental dynamics lies in waste (mis-)management, which sets where boundary values might be. Minimum requirements for populations are under-defined: it is the distribution of resources, opportunities and waste that shape what is a safe space and for whom. Discussion: We suggest that PBc is not different or innovative enough to break 'Cassandra's dilemma' and ensure scientific research effectively guides humanity towards sustainable development. For this, key issues of equality must be addressed, un-sustainability must be framed as a problem of today, rather than projected into the future, and scientific foundations of frameworks such as PBc must be broadened and diversified

Short and long distance contributions to B→K∗γγB \to K^* \gamma \gamma

We study the decay of the neutral B meson to $K^* \gamma \gamma$ within the framework of the Standard Model, including long distance contributions.Comment: 14 pages, 2 figures; A sign error in the numerical estimation corrected. Results and figures changed. Results for resonance contributions also updated to match with the experimetal values in the narrow width approximatio

Charge and mass effects on the evaporation of higher-dimensional rotating black holes

To study the dynamics of discharge of a brane black hole in TeV gravity scenarios, we obtain the approximate electromagnetic field due to the charged black hole, by solving Maxwell's equations perturbatively on the brane. In addition, arguments are given for brane metric corrections due to backreaction. We couple brane scalar and brane fermion fields with non-zero mass and charge to the background, and study the Hawking radiation process using well known low energy approximations as well as a WKB approximation in the high energy limit. We argue that contrary to common claims, the initial evaporation is not dominated by fast Schwinger discharge.Comment: Published version. Minor typos corrected. 29 pages, 5 figure

Semiclassical Solution of the Quantum Hydrodynamic Equation for Trapped Bose-condensed Gas in the l=0 Case

In this paper the quantum hydrodynamic equation describing the collective, low energy excitations of a dilute atomic Bose gas in a given trapping potential is investigated with the JWKB semiclassical method. In the case of spherically symmetric harmonic confining potential a good agreement is shown between the semiclassical and the exact energy eigenvalues as well as wave functions. It is also demonstrated that for larger quantum numbers the calculation of the semiclassical wave function is numerically more stable than the exact polynomial with large alternating coefficients.Comment: 12 pages, 7 figure

Continuous loading of a magnetic trap

We have realized a scheme for continuous loading of a magnetic trap (MT). ^{52}Cr atoms are continuously captured and cooled in a magneto-optical trap (MOT). Optical pumping to a metastable state decouples atoms from the cooling light. Due to their high magnetic moment (6 Bohr magnetons), low-field seeking metastable atoms are trapped in the magnetic quadrupole field provided by the MOT. Limited by inelastic collisions between atoms in the MOT and in the MT, we load 10^8 metastable atoms at a rate of 10^8 atoms/s below 100 microkelvin into the MT. After loading we can perform optical repumping to realize a MT of ground state chromium atoms.Comment: 4 pages, 4 figures, version 2, modified references, included additional detailed information, minor changes in figure 3 and in tex