Publications by Joseph Conlon

ALP conversion and the soft X-ray excess in the outskirts of the Coma cluster


D Kraljic, M Rummel, JP Conlon

A 3.55 keV line from DM -> a -> gamma predictions for cool-core and non-cool-core clusters


JP Conlon, AJ Powell

Observational consistency and future predictions for a 3.5 keV ALP to photon line


PD Alvarez, JP Conlon, FV Day, MCD Marsh, M Rummel

3.55 keV photon lines from axion to photon conversion in the Milky Way and M31


JP Conlon, FV Day

A note on the magnitude of the flux superpotential


M Cicoli, JP Conlon, A Maharana, F Quevedo

3.55 keV photon line and its morphology from a 3.55 keV axionlike particle line

PHYSICAL REVIEW D 90 (2014) ARTN 023540

M Cicoli, JP Conlon, MCD Marsh, M Rummel

Soft X-ray excess in the Coma cluster from a Cosmic Axion Background


S Angus, JP Conlon, MCD Marsh, AJ Powell, LT Witkowski

Excess Astrophysical Photons from a 0.1–1 keV Cosmic Axion Background

Physics Review Letters 111 (2013) 15130

J Conlon, MCD Marsh

Superpotential de-sequestering in string models

Journal of High Energy Physics 2013 (2013)

M Berg, JP Conlon, D Marsh, LT Witkowski

Non-perturbative superpotential cross-couplings between visible sector matter and Kähler moduli can lead to significant flavour-changing neutral currents in compactifications of type IIB string theory. Here, we compute corrections to Yukawa couplings in orbifold models with chiral matter localised on D3-branes and non-perturbative effects on distant D7-branes. By evaluating a threshold correction to the D7-brane gauge coupling, we determine conditions under which the non-perturbative corrections to the Yukawa couplings appear. The flavour structure of the induced Yukawa coupling generically fails to be aligned with the tree-level flavour structure. We check our results by also evaluating a correlation function of two D7-brane gauginos and a D3-brane Yukawa coupling. Finally, by calculating a string amplitude between n hidden scalars and visible matter we show how non-vanishing vacuum expectation values of distant D7-brane scalars, if present, may correct visible Yukawa couplings with a flavour structure that differs from the tree-level flavour structure. © 2013 SISSA, Trieste, Italy.

Soft supersymmetry breaking in anisotropic LARGE volume compactifications


S Angus, JP Conlon

Cosmological natural selection and the purpose of the universe

Complexity 18 (2013) 48-56

A Gardner, JP Conlon

The cosmological natural selection (CNS) hypothesis holds that the fundamental constants of nature have been fine-tuned by an evolutionary process in which universes produce daughter universes via the formation of black holes. Here, we formulate the CNS hypothesis using standard mathematical tools of evolutionary biology. Specifically, we capture the dynamics of CNS using Price's equation, and we capture the adaptive purpose of the universe using an optimization program. We establish mathematical correspondences between the dynamics and optimization formalisms, confirming that CNS acts according to a formal design objective, with successive generations of universes appearing designed to produce black holes. © 2013 Wiley Periodicals, Inc.

Dark radiation in LARGE volume models

PHYSICAL REVIEW D 87 (2013) ARTN 043520

M Cicoli, JP Conlon, F Quevedo

Moduli redefinitions and moduli stabilisation

Journal of High Energy Physics 2010 (2010)

JP Conlon, FG Pedro

Field redefinitions occur in string compactifications at the one loop level. We review arguments for why such redefinitions occur and study their effect on moduli stabilisation and supersymmetry breaking in the LARGE volume scenario. For small moduli, although the effect of such redefinitions can be larger than that of the α' corrections in both the Kähler and scalar potentials, they do not alter the structure of the scalar potential. For the less well motivated case of large moduli, the redefinitions can dominate all other terms in the scalar potential. We also study the effect of redefinitions on the structure of supersymmetry breaking and soft terms. © SISSA 2010.

Gauge threshold corrections for local type-IIB/F-theory GUTs

PHYSICAL REVIEW D 80 (2009) ARTN 106004

JP Conlon, E Palti

Volume Modulus Inflation and the Gravitino Mass Problem

ArXiv (0)

JP Conlon, R Kallosh, A Linde, F Quevedo

The Hubble constant during the last stages of inflation in a broad class of models based on the KKLT mechanism should be smaller than the gravitino mass, H <~ m_{3/2}. We point out that in the models with large volume of compactification the corresponding constraint typically is even stronger, H <~ m_{3/2}^{3/2}, in Planck units. In order to address this problem, we propose a class of models with large volume of compactification where inflation may occur exponentially far away from the present vacuum state. In these models, the Hubble constant during inflation can be many orders of magnitude greater than the gravitino mass. We introduce a toy model describing this scenario, and discuss its strengths and weaknesses.

Continuous Global Symmetries and Hyperweak Interactions in String Compactifications

ArXiv (0)

CP Burgess, JP Conlon, L-Y Hung, CH Kom, A Maharana, F Quevedo

We revisit general arguments for the absence of exact continuous global symmetries in string compactifications and extend them to D-brane models. We elucidate the various ways approximate continuous global symmetries arise in the 4-dimensional effective action. In addition to two familiar methods - axionic Peccei-Quinn symmetries and remnant global abelian symmetries from Green-Schwarz gauge symmetry breaking - we identify new ways to generate approximate continuous global symmetries. Two methods stand out, both of which occur for local brane constructions within the LARGE volume scenario of moduli stabilisation. The first is the generic existence of continuous non-abelian global symmetries associated with local Calabi-Yau isometries. These symmetries are exact in the non-compact limit and are spontaneously broken by the LARGE volume, with breaking effects having phenomenologically interesting sizes \sim 0.01 for plausible choices for underlying parameters. Such approximate flavour symmetries are phenomenologically attractive and may allow the fermion mass hierarchies to be connected to the electroweak hierarchy via the large volume. The second is the possible existence of new hyper-weak gauge interactions under which Standard Model matter is charged, with \alpha_{HW} \sim 10^{-9}. Such groups arise from branes wrapping bulk cycles and intersecting the local (resolved) singularity on which the Standard Model is supported. We discuss experimental bounds for these new gauge bosons and their interactions with the Standard Model particles.

Wave Functions and Yukawa Couplings in Local String Compactifications

ArXiv (0)

JP Conlon, A Maharana, F Quevedo

We consider local models of magnetised D7 branes in IIB string compactifications, focussing on cases where an explicit metric can be written for the local 4-cycle. The presence of an explicit metric allows analytic expressions for the gauge bundle and for the chiral matter wavefunctions through solving the Dirac and Laplace equations. The triple overlap of the normalised matter wavefunctions generates the physical Yukawa couplings. Our main examples are the cases of D7 branes on P1xP1 and P2. We consider both supersymmetric and non-supersymmetric gauge backgrounds and both Abelian and non-Abelian gauge bundles. We briefly outline potential phenomenological applications of our results.

Systematics of Moduli Stabilisation in Calabi-Yau Flux Compactifications

ArXiv (0)

V Balasubramanian, P Berglund, JP Conlon, F Quevedo

We study the large volume limit of the scalar potential in Calabi-Yau flux compactifications of type IIB string theory. Under general circumstances there exists a limit in which the potential approaches zero from below, with an associated non-supersymmetric AdS minimum at exponentially large volume. Both this and its de Sitter uplift are tachyon-free, thereby fixing all Kahler and complex structure moduli, which has been difficult to achieve in the KKLT scenario. Also, for the class of vacua described in this paper, the gravitino mass is independent of the flux discretuum, whereas the ratio of the string scale to the 4d Planck scale is hierarchically small but flux dependent. The inclusion of alpha' corrections plays a crucial role in the structure of the potential. We illustrate these ideas through explicit computations for a particular Calabi-Yau manifold.

Type IIA Orientifolds on General Supersymmetric Z_N Orbifolds

ArXiv (0)

R Blumenhagen, JP Conlon, K Suruliz

We construct Type IIA orientifolds for general supersymmetric Z_N orbifolds. In particular, we provide the methods to deal with the non-factorisable six-dimensional tori for the cases Z7, Z8, Z8', Z12 and Z12'. As an application of these methods we explicitly construct many new orientifold models.

On the Explicit Construction and Statistics of Calabi-Yau Flux Vacua

ArXiv (0)

JP Conlon, F Quevedo

We explicitly construct and study the statistics of flux vacua for type IIB string theory on an orientifold of the Calabi-Yau hypersurface $P^4_{[1,1,2,2,6]}$, parametrised by two relevant complex structure moduli. We solve for these moduli and the dilaton field in terms of the set of integers defining the 3-form fluxes and examine the distribution of vacua. We compare our numerical results with the predictions of the Ashok-Douglas density $\det (-R - \omega)$, finding good overall agreement in different regions of moduli space. The number of vacua are found to scale with the distance in flux space. Vacua cluster in the region close to the conifold singularity. Large supersymmetry breaking is more generic but supersymmetric and hierarchical supersymmetry breaking vacua can also be obtained. In particular, the small superpotentials and large dilaton VEVs needed to obtain de Sitter space in a controllable approximation are possible but not generic. We argue that in a general flux compactification, the rank of the gauge group coming from D3 branes could be statistically preferred to be very small.