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Dr John McDonald

Dr John McDonald

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C21 Physics Building
Lancaster University
Bailrigg
Lancaster
United Kingdom
LA1 4YB

+44 (0)1524 592845

Research Interests

My research area is the intersection of particle physics and cosmology, known as particle cosmology or astro-particle physics.

My past and present research interests include:

Dark matter models (thermal relic MSSM neutralino and non-thermal gravitino dark matter, Higgs portal gauge singlet scalar dark matter, RH sneutrino condensate dark matter, alternative thermal production ("freeze-in") mechanisms for MeV and keV dark matter), the cosmology of the minimal supersymmetric standard model (MSSM) and its extensions (flat directions, Affleck-Dine baryogenesis and leptogenesis, Q-ball formation and decay, curvatons and right-handed sneutrinos), inflation models (non-minimally coupled scalar inflation ("Higgs Inflation"), sub-Planckian axion inflation, supersymmetric hybrid inflation models, oscillon formation and reheating) and baryogenesis (Affleck-Dine, electroweak, baryon-to-dark matter ratio ("Baryomorphosis")).

My most recent research focuses on the following themes:

 

(i) Hemispherical asymmetry of the CMB temperature fluctuations

The cosmic microwave background radiation (CMB) is the remnant radiation from the Big Bang. It has a mean temperature T = 2.725 K, on top of which there are temperature fluctuations of magnitude about 1/10000 of the mean temperature. Analysis of the temperature fluctuations observed by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and ESA's Planck satellite have found that there is an asymmetry in the magnitude of the temperature fluctuations observed on one side of the sky compared to the opposite side, with a 12-14% difference. This is known as the Hemispherical Power Asymmetry. It is not expected to exist in conventional cosmology models, which predict a difference of no more than 6%. I am presently studying unconventional models based on cosmological phase transitions which occur during inflation, which are able to generate an asymmetric scalar field on the scale of the observed Universe. The hope is that this field may be able modulate the CMB temperature fluctuations across the sky, without introducing unwanted features such as a change in the statistics of the microwave fluctuations or a change in the mean CMB temperature.

[Publications:    "Isocurvature and Curvaton Perturbations with Red Power Spectrum and Large Hemispherical Asymmetry", arXiv:1305.0525 [astro-ph.CO], JCAP 1307 (2013) 043;  "Hemispherical Power Asymmetry from Scale-Dependent Modulated Reheating", arXiv:1309.1122 [astro- ph.CO], JCAP 1311 (2013) 041; "Hemispherical Power Asymmetry from a Space-Dependent Component of the Adiabatic Power Spectrum", arXiv:1403.2076 [astro-ph.CO], Phys.Rev. D89 (2014) 127303; "Negative Running of the Spectral Index, Hemispherical Asymmetry and the Consistency of Planck with Large r", arXiv:1403.6650 [astro-ph.CO], JCAP 1411 (2014) 012.]

 

 (ii) Sub-Planckian inflation models with a large gravitational wave signature

     Inflation might be able to generate primordial gravitational waves, whose detection would serve as a 'smoking gun' for inflation as the explanation of the observed structure of the Universe. However, in order to generate a large gravitational wave signal, the simplest inflation models require scalar fields which are larger than the Planck scale, the scale at which quantum gravity effects become large and the new physics associated with the unification of gravity and other particles and forces is expected to become important. Therefore conventional inflation theories which can generate a large gravitational wave signal are expected to break down. This raises the question of whether it is possible to construct inflation models which can generate a large gravitation wave signal but which do not require scalar field values larger than the Planck scale. I am studying field theory inflation models based on simple axion models which achieve this and which make clear predictions for both the magnitude of the gravitational wave signal ("tensor-to-scalar ratio") and the slope of CMB fluctuation spectrum ("scalar spectral index").

[Publications: "Sub-Planckian Two-Field Inflation Consistent with the Lyth Bound", arXiv:1404.4620 [hep-ph], JCAP 1409 (2014) 09, 027;  "A Minimal Sub-Planckian Axion Inflation Model with Large Tensor-to-Scalar Ratio", arXiv:1407.7471 [hep-ph], JCAP 1501 (2015) 018; "Signatures of Planck Corrections in a Spiralling Axion Inflation Model", arXiv:1412.6943 [hep-ph].] 

 

Web Links

My Research Page: http://www.physics.lancs.ac.uk/research/capg/researchJM.html

Cosmology and Astroparticle Physics Group: http://www.physics.lancs.ac.uk/research/capg/

Lancaster-Manchester-Sheffield Consortium for Fundamental Physics: http://www.physics.lancs.ac.uk/research/capg/

John McDonald's Publications

2015

A minimal sub-Planckian axion inflation model with large tensor-to-scalar ratio

McDonald, J. 01/2015 In : Journal of Cosmology and Astroparticle Physics. 2015, 1, 8 p.018

Research output: Contribution to journalJournal article

2014

Negative running of the spectral index, hemispherical asymmetry and the consistency of Planck with large r

McDonald, J. 11/2014 In : Journal of Cosmology and Astroparticle Physics. 2014, 11, 9 p.012

Research output: Contribution to journalJournal article

Sub-Planckian two-field inflation consistent with the Lyth bound

McDonald, J. 09/2014 In : Journal of Cosmology and Astroparticle Physics. 2014, 9, 9 p.027

Research output: Contribution to journalJournal article

Hemispherical power asymmetry from a space-dependent component of the adiabatic power spectrum

McDonald, J. 26/06/2014 In : Physical Review D. 89, 12, 5 p.127303

Research output: Contribution to journalJournal article

2013

Hemispherical power asymmetry from scale-dependent modulated reheating

McDonald, J. 19/11/2013 In : Journal of Cosmology and Astroparticle Physics. 2013, 11, 15 p.041

Research output: Contribution to journalJournal article

Dark matter gravitinos and baryons via Q-ball decay in the gauge-mediated MSSM

Doddato, F. & McDonald, J. 3/07/2013 In : Journal of Cosmology and Astroparticle Physics. 2013, 7, 24 p.004

Research output: Contribution to journalJournal article

Isocurvature and curvaton perturbations with red power spectrum and large hemispherical asymmetry

McDonald, J. 07/2013 In : Journal of Cosmology and Astroparticle Physics. 2013, 7, 16 p.043

Research output: Contribution to journalJournal article

Explaining the dark energy, baryon and dark matter coincidence via domain-dependent random densities

McDonald, J. 05/2013 In : Journal of Cosmology and Astroparticle Physics. 2013, 5, 15 p.019

Research output: Contribution to journalJournal article

Baryon-to-dark matter ratio from random angular fields

McDonald, J. 01/2013 In : Journal of Cosmology and Astroparticle Physics. 2013, 1, 12 p.025

Research output: Contribution to journalJournal article

2012

Unitarity-violation in generalized Higgs inflation models

Lerner, R. N. & McDonald, J. 11/2012 In : Journal of Cosmology and Astroparticle Physics. 2012, 11, 20 p.019

Research output: Contribution to journalJournal article

Anthropically selected baryon number and isocurvature constraints

McDonald, J. 10/2012 In : Journal of Cosmology and Astroparticle Physics. 2012, 10, 15 p.005

Research output: Contribution to journalJournal article

New Q-ball Solutions in Gauge-Mediation, Affleck-Dine Baryogenesis and Gravitino Dark Matter

Doddato, F. & McDonald, J. 20/06/2012 In : Journal of Cosmology and Astroparticle Physics. 12, 6, 31

Research output: Contribution to journalJournal article

2011

Simultaneous Generation of WIMP Miracle-like Densities of Baryons and Dark Matter

McDonald, J. 10/11/2011 In : Physical Review D. 84, 10, 9 p.103514

Research output: Contribution to journalJournal article

Distinguishing Higgs inflation and its variants

N. Lerner, R. & McDonald, J. 21/06/2011 In : Physical Review D. 83, 12, 15 p.123522

Research output: Contribution to journalJournal article

Affleck-Dine baryogenesis, condensate fragmentation and gravitino dark matter in gauge-mediation with a large messenger mass

Doddato, F. & McDonald, J. 06/2011 In : Journal of Cosmology and Astroparticle Physics. 2011, 6, 17 p.8

Research output: Contribution to journalJournal article

Relating the baryon asymmetry to the thermal relic dark matter density

McDonald, J. 12/04/2011 In : Physical Review D. 83, 8, 7 p.083509

Research output: Contribution to journalJournal article

2010

A Unitarity-Conserving Higgs Inflation Model

N. Lerner, R. & McDonald, J. 19/11/2010 In : Physical Review D. 82, 10, 5 p.103525

Research output: Contribution to journalJournal article

Cosmological evolution of scalar fields and gravitino dark matter in gauge mediation at low reheating temperatures

Ferrantelli, A. & McDonald, J. 02/2010 In : Journal of Cosmology and Astroparticle Physics. 2010, 2, 21 p.3

Research output: Contribution to journalJournal article

Cosmic Ray Anomalies and Dark Matter Annihilation to Muons via a Higgs Portal Hidden Sector

Kohri, K., McDonald, J. & Sahu, N. 28/01/2010 In : Physical Review D – Particles and Fields. 81, 2, 11 p.023530

Research output: Contribution to journalJournal article

Higgs inflation and naturalness

N. Lerner, R. & McDonald, J. 2010 In : Journal of Cosmology and Astroparticle Physics. 2010, 4, 10 p.15

Research output: Contribution to journalJournal article

2009

Gauge singlet scalar as inflaton and thermal relic dark matter

N. Lerner, R. & McDonald, J. 8/12/2009 In : Physical Review D. 80, 12, 14 p.123507

Research output: Contribution to journalJournal article

Enhanced Dark Matter Annihilation Rate for Positron and Electron Excesses from Q-ball Decay

McDonald, J. 6/10/2009 In : Physical Review Letters. 103, 15, 4 p.151301

Research output: Contribution to journalJournal article

keV Warm Dark Matter via the Supersymmetric Higgs Portal

McDonald, J. & Sahu, N. 21/05/2009 In : Physical Review D – Particles and Fields. 79, 10, 6 p.103523

Research output: Contribution to journalJournal article

Cosmological constraints on unparticles as continuous mass particles.

McDonald, J. 16/03/2009 In : Journal of Cosmology and Astroparticle Physics. 2009, 3, p. 19

Research output: Contribution to journalJournal article

2008

Supersymmetric inflation and baryogenesis via Extra-Flat directions of the MSSM.

McDonald, J. & Seto, O. 07/2008 In : Journal of Cosmology and Astroparticle Physics. 2008, 7, p. 15

Research output: Contribution to journalJournal article

Z(2)-Singlino Dark Matter in a Portal-Like Extension of the Minimal Supersymmetric Standard Model.

McDonald, J. & Sahu, N. 06/2008 In : Journal of Cosmology and Astroparticle Physics. 2008, 6, p. 26

Research output: Contribution to journalJournal article

Type II See-Saw at Collider, Lepton Asymmetry and Singlet Scalar Dark Matter.

McDonald, J., Sahu, N. & Sarkar, U. 04/2008 In : Journal of Cosmology and Astroparticle Physics. 2008, 4, p. 37

Research output: Contribution to journalJournal article

Supergravity and two-field inflation effects in right-handed sneutrino modified D-term inflation.

Lin, C-M. & McDonald, J. 25/03/2008 In : Physical Review D. 77, 6, 9 p.063529

Research output: Contribution to journalJournal article

2007

Right-handed sneutrino condensate cold dark matter and the baryon-to-dark matter ratio.

McDonald, J. 2/01/2007 In : Journal of Cosmology and Astroparticle Physics. 2007, 01, p. 001

Research output: Contribution to journalJournal article

2006

Supergravity Modification of D-term Hybrid Inflation: Solving the Cosmic String and Spectral Index Problem via a Right-Handed Sneutrino.

McDonald, J. & Lin, C. M. 1/09/2006 In : Physical Review D. 74, 6, p. 063510

Research output: Contribution to journalJournal article

F-term inflation Q-balls

McDonald, J. F. 2006 In : Physical Review Series D. 73, 043501

Research output: Contribution to journalJournal article

2005

Simulations of the end of supersymmetric hybrid inflation and nontopological soliton formation.

Broadhead, M. & McDonald, J. 15/08/2005 In : Physical Review D. 72, 4, p. 043519

Research output: Contribution to journalJournal article

2004

Condition for successful right-handed Majorana Sneutrino curvaton.

McDonald, J. 16/09/2004 In : Physical Review D. 70, 6, 11 p.063520

Research output: Contribution to journalJournal article

Flat direction dynamics in a non-topological soliton-dominated universe.

McDonald, J. 08/2004 In : Journal of Cosmology and Astroparticle Physics. 2004, 8, p. 002

Research output: Contribution to journalJournal article

Supersymmetric curvatons and phase-induced curvaton fluctuations.

McDonald, J. 19/05/2004 In : Physical Review D. 69, 10, p. 103511

Research output: Contribution to journalJournal article

Two-field Q-ball solutions of supersymmetric hybrid inflation.

Broadhead, M. & McDonald, J. 2004 In : Physical Review D. 69, 6, p. 063510 5 p.063510

Research output: Contribution to journalJournal article

2003

Curvaton Potential Terms, Scale-Dependent Perturbation Spectra and Chaotic Initial Conditions

McDonald, J. 12/12/2003 In : Journal of Cosmology and Astroparticle Physics. 2003, 12, 8 p.005

Research output: Contribution to journalJournal article

Growth of inflaton perturbations and the post-inflation era in supersymmetric hybrid inflation models

McDonald, J. 15/10/2003 In : Physical Review D. 68, 8, p. 083502 12 p.

Research output: Contribution to journalJournal article

Right-handed sneutrinos as curvatons.

McDonald, J. 8/08/2003 In : Physical Review D. 68, 4, 10 p.043505

Research output: Contribution to journalJournal article

F-term Hybrid Inflation, the η-problem and Extra Dimensions

McDonald, J. 16/01/2003 In : Journal of High Energy Physics. 2002, 12, 10 p.029

Research output: Contribution to journalJournal article

2002

Inflaton condensate fragmentation in hybrid inflation models

McDonald, J. 22/08/2002 In : Physical Review D. 66, 4, p. 043525 8 p.

Research output: Contribution to journalJournal article

Thermally-generated Gauge Singlet Scalars as Self-Interacting Dark Matter.

McDonald, J. 15/02/2002 In : Physical Review Letters. 88, 9, p. 091304 4 p.

Research output: Contribution to journalJournal article

2001

Non-thermal dark matter, high energy cosmic rays and late-decaying particles from inflationary quantum fluctuations

McDonald, J. 28/06/2001 In : Physics Letters B. 511, 1, p. 1-10 10 p.

Research output: Contribution to journalJournal article

Q-ball evolution, B-ball baryogenesis and the fB problem

McDonald, J. 6/04/2001 In : Journal of High Energy Physics. 2001, 03, p. 022 23 p.

Research output: Contribution to journalJournal article

Dynamical cosmological constant from a very recent phase transition

McDonald, J. 25/01/2001 In : Physics Letters B. 498, 3-4, p. 263-271 9 p.

Research output: Contribution to journalJournal article

2000

Inflationary Affleck-Dine scalar dynamics and isocurvature perturbations

Enqvist, K. & McDonald, J. 13/07/2000 In : Physical Review D. 62, 4, 8 p.043502

Research output: Contribution to journalJournal article

Flat direction condensate instabilities in the MSSM

Enqvist, K., Jokinen, A. & McDonald, J. 15/06/2000 In : Physics Letters B. 483, 1-3, p. 191-195 5 p.

Research output: Contribution to journalJournal article

Naturally Large Cosmological Neutrino Asymmetries in the Minimal Supersymmetric Standard Model

McDonald, J. 22/05/2000 In : Physical Review Letters. 84, 21, p. 4798-4801 4 p.

Research output: Contribution to journalJournal article

Current Students

Research students currently supervised by John McDonald include: