String Phenomenology 2019

Session

Parallel Session

25 Jun 2019, 14:30

4/3-006 - TH Conference Room (CERN)

76. No-Go theorems for ekpyrosis from ten-dimensional supergravity

Kunihito Uzawa (Kwansei Gakuin University)

25/06/2019, 14:30

In this talk, we present whether the new ekpyrotic scenario can be embedded into ten-dimensional supergravity. We use that the scalar potential obtained from flux compactifications of type II supergravity with sources has a universal scaling with respect to the dilaton and the volume mode. Similar to the investigation of inflationary models, we find very strong constraints ruling out ekpyrosis...

77. Black Hole Superradiance Constraints on the KS Axiverse

Viraf Mehta (University of Goettingen)

25/06/2019, 14:45

We discuss imposing physical constraints on the recently generated Kreuzer-Skarke Axiverse, namely the application of mass limits coming from black hole superradiance. We briefly touch on how our approach can also be applied to other physical limits on axion masses and decay constants to rule out previously viable string backgrounds.

78. Moduli Stars

Dr Francesco Muia

25/06/2019, 15:00

The recent direct detection of gravitational waves (GWs) has opened a new window of observation for physical phenomena in which gravity is the dominant interaction. Collisions of black holes and neutron stars have been observed and a plethora of new events, even involving new physics, are expected to be detected in the next few years. It is natural to explore alternative physical objects that...

79. Moduli Portal between visible and hidden sectors

Igor Broeckel (University of Bologna)

25/06/2019, 15:15

We investigate the possibility of Moduli mediators between the visible and hidden sector in the context of the LVS.

80. Spontaneous dark-matter mass generation along cosmological attractors in string theory

Thibaut Coudarchet (Ecole Polytechnique)

25/06/2019, 15:30

I will talk about a new scenario for generating a relic density of non-relativistic dark matter in the framework of heterotic string theory with spontaneously broken supersymmetry and at finite temperature. In this scenario, contrary to the standard thermal freeze-out process, dark-matter particles are produced while they are still relativistic and then decouple from the thermal bath because...

81. Shift Symmetric Orbital Inflation

Yvette Welling (Deutsches Elektronen-Synchrotron DESY)

25/06/2019, 15:45

Recent swampland conjectures highlight again the importance of finding viable scenarios for inflation that are not strictly single-field. In particular, one may wonder whether there are multi-field inflationary scenarios that have a similar phenomenology to single field inflation. We present a family of exact models of inflation - dubbed Orbital Inflation - in which the multi-field effects are...

82. Gravitational waves from axion clumps

Sichun Sun (Sapienza University of Rome)

25/06/2019, 16:30

Axionic objects such as axion miniclusters and axion clouds around spinning black holes induce parametric resonances of electromagnetic waves through the axion-photon interaction. Here we discuss various difference gravitational sources from such objects through similar mechanisms.

83. Observing axion potentials through gravitational waves

Evangelos Sfakianakis (University of Illinois at Urbana-Champaign)

25/06/2019, 16:45

I will discuss the the production of gravitational waves which are sourced by the tensor perturbation of SU(2) gauge fields coupled to a spectator axion field. Even though string theory constructions provide a variety of potentials, they can be categorized based on the number of non-stationary inflection points. I will present the resulting GW templates arising from each potential type. I will...

84. Wavefunctions and their implications on S^2 with flux and branes

Yoshiyuki Tatsuta (Waseda Univ.)

25/06/2019, 17:00

We formulate a six dimensional U(1) gauge theory compactified on a (two dimensional) sphere S^2 with flux and localized brane sources. Profiles of the lowest Kaluza-Klein (KK) wavefunctions and their masses are derived analytically. In contrast to ordinary sphere compactifications, the above setup can lead to the degeneracy of and the sharp localizations of the linearly independent lowest KK...

85. Matrix model and Yukawa couplings on the magnetized noncommutative torus

Honda Masaki (Waseda University)

25/06/2019, 17:15

The IKKT model is proposed as a non-perturbative formulation of superstring theory. I consider the magnetized toroidal compactifications of the IKKT model. I find that the chirality and the generation structure are almost same with the magnetized toroidal compactifications of the super Yang-Mills theory. In addition, I compute the Yukawa couplings including a noncommutative parameter. In...

86. Discrete Flavor Symmetries from Orbifold GUTs

Andreas Muetter (Technical University of Munich)

25/06/2019, 17:30

In this talk, we show that in orbifold GUT models discrete symmetries can be understood as remnants of gauge symmetries that are broken by orbifold boundary conditions. We present a systematic way to determine the discrete symmetries that survive the orbifolding. In particular, we derive universal conditions that need to be fulfilled in order to preserve any discrete symmetry. Finally, some...

87. Classification of Left-Right Symmetric Heterotic String vacua

Benjamin Percival (liverpool)

25/06/2019, 17:45

I will briefly describe the classification approach within the free fermionic formalism, then discuss techniques beyond the random generation classification. In particular, explorations of 'fertile regions' within left-right symmetric models that are pre-selected at the SO(10) level for phenomenological favourability. Finally, we will discuss the application of machine learning techniques...

100. M5 branes and Theta Functions

Rui Sun (Yau mathematical science center, Tsinghua University)

27/06/2019, 14:30

We propose quantum states for Little String Theories arising from M5 branes probing A- and D-type singularities. This extends Witten's picture of M5 brane partition functions as theta functions to this more general setup. Compactifying the world-volume of the five-branes on a two-torus, we find that the corresponding theta functions are sections of line bundles over complex 4-tori. This...

102. Cosmological constant at finite string coupling in F-theory flux compactification

Hajime Otsuka (KEK)

27/06/2019, 14:45

We examine vacuum structures of effective theories of moduli fields in the frameworks of Type IIB and F-theory flux compactifications. For two explicit examples, we numerically investigate the distributions of a huge number of local minima of the effective potential in the complex structure and dilaton directions in moduli fields. Interestingly, our results for the distributions of...

103. Branes, quiver gauge theories and discrete symmetries

Jamie Rogers (Liverpool University)

27/06/2019, 15:00

The spaces of zero-energy configurations (moduli spaces of vacua) of supersymmetric QFTs are richly geometrically structured. Realizing quiver gauge theories as the IR descriptions of brane configurations has allowed the recent development of numerous techniques to examine this geometry. I will discuss some of these techniques and how they can be used to investigate the local geometry of...

104. Multi-field Inflation in High-Slope Potentials

Robert Rosati (University of Texas at Austin)

27/06/2019, 15:15

The recent swampland conjectures have ruled out some of the simplest models of single-field inflation. Inspired by the distance conjecture and the high-slope conjecture, I will present two families of multi-field inflationary potentials compatible with the conjectures along the trajectory. One family is a helix-type potential that satisfies the conjectures only locally. This family inflates...

105. Triangulating the Landscape

Andres Rios (Cornell University)

27/06/2019, 15:30

One of the main contributors to the vastness of the string landscape is the immense number of Calabi-Yau (CY) manifolds on which the theory can be compactified. Currently, one of the largest sets of CYs is obtained from hypersurfaces in toric varieties, which result from fine, regular, star triangulations (FRSTs) of reflexive polytopes. In this talk I will present new developments in the study...

125. What does Inflation say about Dark Energy given the Swampland Conjectures?

Jacob Leedom (University of California, Berkeley)

27/06/2019, 15:45

I will discuss the relations between swampland conjectures and observational constraints on both inflation and dark energy. Using the fact that the constant c appearing in the de Sitter conjecture is a universal constant whose value can be determined from inflation, there may be no observable distinction between constant and non-constant models of dark energy. However, the latest modification...