Diversity in the Tail of the Intersecting Brane Landscape

Techniques are developed for exploring the complete space of intersecting brane models on an orientifold. The classification of all solutions for the widely-studied T^6/Z_2 x Z_2 orientifold is made possible by computing all combinations of branes with negative tadpole contributions. This provides the necessary information to systematically and efficiently identify all models in this class with specific characteristics. In particular, all ways in which a desired group G can be realized by a system of intersecting branes can be enumerated in polynomial time. We identify all distinct brane realizations of the gauge groups SU(3) x SU(2) and SU(3) x SU(2) x U(1) which can be embedded in any model which is compatible with the tadpole and SUSY constraints. We compute the distribution of the number of generations of "quarks" and find that 3 is neither suppressed nor particularly enhanced compared to other odd generation numbers. The overall distribution of models is found to have a long tail. Despite disproportionate suppression of models in the tail by K-theory constraints, the tail in the distribution contains much of the diversity of low-energy physics structure.Comment: 48 pages, 8 figure

Power of Black Hole Physics: Seeing through the Vacuum Landscape

In this paper we generalize the black hole bound of arXiv:0706.2050 to de Sitter spaces, and apply it to various vacua in the landscape, with a special emphasis on slow-roll inflationary vacua. Non-trivial constraints on the lifetime and the Hubble expansion rate emerge. For example, the general tendency is, that for the fixed number and the increasing mass of the species, vacua must become more curved and more unstable, either classically or quantum mechanically. We also discuss the constraints on the lifetime of vacua in the landscape, due to decay into the neighboring states.Comment: 33 page

Free Fermion Orientifolds

We investigate a class of orientifold models based on tensor products of 18 Ising models. Using the same search criteria as for the comparable case of Gepner model orientifolds we find that there are no three-family standard model configurations with tadpole cancellation. Even if we do not impose the latter requirement, we only find one such configuration in the special case of complex free fermions. In order to allow a comparison with other approaches we enumerate the Hodge numbers of the type-IIB theories we obtain. We provide indications that there are fermionic IIB vacua that are not $Z_2\times Z_2$ orbifolds.Comment: 18 pages + Appendix; references adde

Free Fermionic Heterotic Model Building and Root Systems

We consider an alternative derivation of the GSO Projection in the free fermionic construction of the weakly coupled heterotic string in terms of root systems, as well as the interpretation of the GSO Projection in this picture. We then present an algorithm to systematically and efficiently generate input sets (i.e. basis vectors) in order to study Landscape statistics with minimal computational cost. For example, the improvement at order 6 is approximately 10^{-13} over a traditional brute force approach, and improvement increases with order. We then consider an example of statistics on a relatively simple class of models.Comment: Standard Latex, 12 page

Yukawa couplings and masses of non-chiral states for the Standard Model on D6-branes on T6/Z6'

The perturbative leading order open string three-point couplings for the Standard Model with hidden USp(6) on fractional D6-branes on T6/Z6' from arXiv:0806.3039 [hep-th], arXiv:0910.0843 [hep-th] are computed. Physical Yukawa couplings consisting of holomorphic Wilsonian superpotential terms times a non-holomorphic prefactor involving the corresponding classical open string Kaehler metrics are given, and mass terms for all non-chiral matter states are derived. The lepton Yukawa interactions are at leading order flavour diagonal, while the quark sector displays a more intricate pattern of mixings. While N=2 supersymmetric sectors acquire masses via only two D6-brane displacements - which also provide the hierarchies between up- and down-type Yukawas within one quark or lepton generation -, the remaining vector-like states receive masses via perturbative three-point couplings to some Standard Model singlet fields with vevs along flat directions. Couplings to the hidden sector and messengers for supersymmetry breaking are briefly discussed.Comment: 52 pages (including 8p. appendix); 5 figures; 14 tables; v2: discussion in section 4.1.3 extended, footnote 5 added, typos corrected, accepted by JHE

The UEFA EURO 2012 anti-doping programme - scientific review

The final tournament of the UEFA European Football Championship is one of the top sporting events in the world, and a high-profile event of this kind requires a well-planned and well-executed anti-doping programme to ensure the integrity of results in the competition. UEFA EURO 2012 presented a unique logistical challenge, with the tournament spread across two countries, both covering a large geographical area. This paper discusses the planning and delivery of both the pre tournament out-of-competition (OOC) testing programme and the in-competition (IC) programme, as well as reviewing the activities of doping control officers (DCOs), the whereabouts programme and assessing the sample collection and transport process. The analytical approach applied is also discussed, along with an overview of the distribution of T/E ratios and blood parameters

Intersecting D-Branes on Shift Z2 x Z2 Orientifolds

We investigate Z2 x Z2 orientifolds with group actions involving shifts. A complete classification of possible geometries is presented where also previous work by other authors is included in a unified framework from an intersecting D-brane perspective. In particular, we show that the additional shifts not only determine the topology of the orbifold but also independently the presence of orientifold planes. In the second part, we work out in detail a basis of homological three cycles on shift Z2 x Z2 orientifolds and construct all possible fractional D-branes including rigid ones. A Pati-Salam type model with no open-string moduli in the visible sector is presented.Comment: 36 pages, 4 figures, refs. adde

On Susy Standard-like models from orbifolds of D=6 Gepner orientifolds

As a further elaboration of the proposal of Ref. [1] we address the construction of Standard-like models from configurations of stacks of orientifold planes and D-branes on an internal space with the structure ${(Gepner model)^{c=6} \times T^2}/Z_N$. As a first step, the construction of D=6 Type II B orientifolds on Gepner points, in the diagonal invariant case and for both, odd and even, affine levels is discussed. We build up the explicit expressions for B-type boundary states and crosscaps and obtain the amplitudes among them. From such amplitudes we read the corresponding spectra and the tadpole cancellation equations. Further compactification on a T^2 torus, by simultaneously orbifolding the Gepner and the torus internal sectors, is performed. The embedding of the orbifold action in the brane sector breaks the original gauge groups and leads to N=1 supersymmetric chiral spectra. Whenever even orbifold action on the torus is considered, new branes, with worldvolume transverse to torus coordinates, must be included. The detailed rules for obtaining the D=4 model spectra and tadpole equations are shown. As an illustration we present a 3 generations Left-Right symmetric model that can be further broken to a MSSM model.Comment: 40 pages, 2 figures, added references, table 3 correcte

Seasonality in Major Depressive Disorder: Effect of Sex and Age

Background: Aside from the concept of seasonal affective disorder, the evidence for a seasonal pattern (SP) of major depressive disorder (MDD) is controversial. Furthermore, the effect of sex and age is still unclear. Methods: This is a nationwide, registry-based study assessing all inpatient admissions in mental health hospitals due to MDD episodes according to ICD-10 (moderate (F32/33.1), severe (F32/33.2) and severe with psychotic features (F32/33.3)) in Austria across 14 years. Calculations were based on deviations from expected monthly admissions. Results: The sample comprised 231,824 hospitalisations (36.8% men) for MDD. A significant SP (p=0.001) in moderate and severe depressive episodes in both women and men with decreased admission rates in the summer months and December was detected. In psychotic depression a significant SP was only evidenced in women (p = 0.002, men: p = 0.291). Patients older than 55 years had a reduced SP compared to those being younger. Limitations: Only anonymised admission data of inpatient treatments were available. Hospitalization rates cannot fully be equated to the occurrence of MDD. Conclusions: The current study indicates a seasonal variation in MDD symptoms that may go beyond seasonal affective disorder. Knowledge about the predictability of depressive symptoms in patients should encourage preventive strategies

DBI Inflation using a One-Parameter Family of Throat Geometries

We demonstrate the possibility of examining cosmological signatures in the DBI inflation setup using the BGMPZ solution, a one-parameter family of geometries for the warped throat which interpolate between the Maldacena-Nunez and Klebanov-Strassler solutions. The warp factor is determined numerically and subsequently used to calculate cosmological observables including the scalar and tensor spectral indices, for a sample point in the parameter space. As one moves away from the KS solution for the throat the warp factor is qualitatively different, which leads to a significant change for the observables, but also generically increases the non-Gaussianity of the models. We argue that the different models can potentially be differentiated by current and future experiments.Comment: 17 pages, 10 figures; v2: section 4 expanded, references added; v3: typos fixe