Boosting the Standard Model Higgs Signal with the Template Overlap Method

We show that the Template Overlap Method can improve the signal to background ratio of boosted $H\to b \bar b$ events produced in association with a leptonically decaying $W$. We introduce several improvements on the previous formulations of the template method. Varying three-particle template subcones increases the rejection power against the backgrounds, while sequential template generation ensures an efficient coverage in template phase space. We integrate b-tagging information into the template overlap framework and introduce a new template based observable, the template stretch. Our analysis takes into account the contamination from the charm daughters of top decays in $t\bar t$ events, and includes nearly-realistic effects of pileup and underlying events. We show that the Template Overlap Method displays very low sensitivity to pileup, hence providing a self-contained alternative to other methods of pile up subtraction. The developments described in this work are quite general, and may apply to other searches for massive boosted objects.Comment: 28 pages, 35 figures; references added, minor revisions, to appear in JHE

Solar γ\gamma-rays as a Complementary Probe of Dark Matter

We show that observations of solar $\gamma$-rays offer a novel probe of dark matter in scenarios where interactions with the visible sector proceed via a long-lived mediator. As a proof of principle, we demonstrate that there exists a class of models which yield solar $\gamma$-ray fluxes observable with the next generation of $\gamma$-ray telescopes, while being allowed by a variety of current experimental constraints. The parameter space allowed by big bang nucleosynthesis and beam dump experiments naturally leads to mediator lifetimes sufficient to produce observable solar $\gamma$-ray signals. The model allows for solar $\gamma$-ray fluxes up to orders of magnitude larger compared to dwarf spheroidal galaxies, without reaching equilibrium between dark matter annihilation and capture rate. Our results suggest that solar $\gamma$-ray observations are complementary, and in some cases superior, to existing and future dark matter detection efforts.Comment: 15 pages + references, 7 figures, v3: Fermi-LAT and HERD sensitivity corrected, minor presentational improvements, matches journal versio

Probing Dark Matter Long-lived Mediators with Solar γ\gamma rays

We show that solar $\gamma$-ray observations can provide a complementary probe of Dark Matter in scenarios where the interactions with the Standard Model proceed via long-lived mediators. For illustration we consider a simplified model which provides solar $\gamma$-ray fluxes observable with the next generation $\gamma$-ray telescopes, while complying with the existing experimental constraints. Our results suggest that solar $\gamma$-ray fluxes can be orders of magnitude larger than the ones from the Galactic center, while being subject to low backgrounds.Comment: 4 pages, 2 figures. To appear in the proceedings of The European Physical Society Conference on High Energy Physics, 5-12 July 2017 in Venice, Ital

Constraints on Resonant Dark Matter Annihilation

Resonant dark matter annihilation drew much attention in the light of recent measurements of charged cosmic ray fluxes. Interpreting the anomalous signal in the positron fraction as a sign of dark matter annihilation in the galactic halo requires cross sections orders of magnitudes higher than the estimates coming from thermal relic abundance. Resonant dark matter annihilation provides a mechanism to bridge the apparent contradiction between thermal relic abundance and the positron data measured by PAMELA and FERMI satellites. In this thesis, we analyze a class of models which allow for dark matter to annihilate through an s-channel resonance. Our analysis takes into account constraints from thermal relic abundance and the recent measurements of charged lepton cosmic ray fluxes, first separately and then simultaneously. Consistency of resonant dark matter annihilation models with thermal relic abundance as measured by WMAP serves to construct a relationship between the full set of masses, couplings and widths involved. Extensive numerical analysis of the full four dimensional parameter space is summarized by simple analytic approximations. The expressions are robust enough to be generalized to models including additional annihilation channels. We provide a separate treatment of resonant annihilation of dark matter in the galac- tic halo. We find model-independent upper limits on halo dark matter annihilation rates and show that the most efficient annihilation mechanism involves s-channel resonances. Widths that are large compared to the energy spread in the galactic halo are capable of saturating unitarity bounds without much difficulty. Partial wave unitarity prevents the so called Sommerfeld factors from producing large changes in cross sections. In addition, the approximations made in Sommerfeld factors break down in the kinematic regions where large cross section enhancements are often cited. Simultaneous constraints from thermal relic abundance and halo annihilation serve to produce new limits on dark matter masses and couplings. Past considerations of only a part of the resonant annihilation parameter set to motivate large annihilation cross section enhancements in the halo while maintaining correct relic abundance are generally incomplete. Taking into account only the resonance mass and width to show that large cross section enhancements are possible does not in principle guarantee that the enhancement will be achieved. We extend the calculation to include the full resonant parameter set. As a result, we obtain new limits on dark matter masses and couplings

Boosted Event Topologies from TeV Scale Light Quark Composite Partners

We propose a new search strategy for quark partners which decay into a boosted Higgs and a light quark. As an example, we consider phenomenologically viable right handed up-type quark partners of mass $\sim 1$ TeV in composite pseudo-Nambu-Goldstone-boson Higgs models within the context of flavorful naturalness. Our results show that $S/B > 1$ and signal significance of $\sim 7\sigma$ is achievable at $\sqrt{s} = 14$ TeV LHC with 35 $fb^{-1}$ of integrated luminosity, sufficient to claim discovery of a new particle. A combination of a multi-dimensional boosted Higgs tagging technique, kinematics of pair produced heavy objects and $b$-tagging serves to efficiently diminish the large QCD backgrounds while maintaining adequate levels of signal efficiency. We present the analysis in the context of effective field theory, such that our results can be applied to any future search for pair produced vector-like quarks with decay modes to Higgs and a light jet.Comment: 18 pages, 7 figures, 5 tables, v2: short discussion added in Sec. 2, references added, corresponds to version published in JHE

Urban identity of Belgrade: perfect chaos, imperfect balance

Using a typology of urban symbolism, the identity of Belgrade is reconstructed on the basis of accounts by a sample of city residents, foreigners and locals, who work in international companies and organizations. The component of behavioral symbolism is found to prevail, referring to the places' atmosphere, mood, spirit, or energy. Next comes material symbolism, particularly in relation to Belgrades' location at the confluence of two rivers, and the Kalemegdan complex overlooking it. All other types of symbolism are much less prominent. Belgrade is described as having a comparatively low global visibility and lacking a readily recognizable landmark. What emerges as a pervasive motif in the different symbolic codes is the attribute of contradiction, and the related qualities of hybridity, liminality, and incompleteness.U radu se, uz pomoć tipologije urbanih simbola, identitet Beograda rekonstruiše na osnovu iskaza uzorka njegovih stanovnika (stranaca i građana Srbije) koji rade u međunarodnim kompanijama i organizacijama. U karakterizacijama dominira bihevioralni simbolizam, koji se odnosi na atmosferu, raspoloženje, duh ili energiju grada. Na drugom mestu je materijalni simbolizam, naročito u vidu geografskog položaja Beograda na ušću dveju reka, uz kompleks Beogradske tvrđave koji se nad njima uzdiže. Svi drugi tipovi simbola su znatno slabije prisutni. Ispitanici smatraju da je Beograd relativno slabo vidljiv u globalnim razmerama i da mu nedostaje opštepoznato obeležje koje bi nepogrešivo simbolizovalo. Uočljivo je da se kroz različite simboličke izražajne jezike provlači motiv protivrečnosti, kao i s njime povezani atributi hibridnosti, liminalnosti i nedovršenosti

Social theory and architecture

The role of architecture through history has always been important because it is a physical frame of social life and also a symbol of social values and aspirations. Architectural creations are influenced by social thought. Modernism is an outstanding example of how social goals have directed planning of the cities. After having analyzed the conditions of its emergence and its characteristics this paper points out the changes brought about by postmodernism. In the end, the attention has been drawn to the place architecture holds in the city of consumption

The Montenegrin capital market: Calendar anomalies

Many researchers have shown that capital markets in CEE countries are weakly efficient in terms of calendar anomalies. The goal of this paper is to investigate whether the capital market in Montenegro is efficient regarding some of these anomalies. The main characteristics of the Montenegrin capital market are briefly explained. The empirical analysis is done on the daily values data of stock market index NEX20. An investigation of the January effect is implemented with the graphical representation of the rate of return for all the months of the seven-year period and by estimation of a regression model of return on index NEX20. The intercept represents the value of the return in January and it is insignificant. The holiday effect, tested by graphical representation for the Statehood Day data, was not present in the whole period. To investigate the turn-of-the-month effect we employed the graphical representation and regression model of the return rate on index NEX20 for the last week of every month and for the rest of the month. The value of the intercept, representing return for the last week of the month, is significant. The absence of some tested calendar anomalies suggests that the Montenegrin capital market is becoming more efficient