A team of physicists from Denmark, Finland and the United Kingdom, led by Dr Matti Herranen University of Copenhagen, says that the spacetime curvature – in effect, gravity – is what may have saved the Universe from collapse immediately after the Big Bang.

Some previous studies have suggested that the production of Higgs particles during the accelerating expansion of the very early Universe (inflation period) should have led to instability and collapse. Physicists have been trying to find out why this didn’t happen, leading to hypotheses that there must be some new physics that will help explain the origins of the Universe that has not yet been discovered.

Dr Herranen and his colleagues, however, believe there is a simpler explanation.

In a new study, published in the journal Physical Review Letters, they describe how the spacetime curvature provided the stability needed for the Universe to survive expansion in that early period.

They investigated the interaction between the Higgs bosons and gravity, taking into account how it would vary with energy.

The results show that even a small interaction would have been enough to stabilize the Universe against decay.

“The Standard Model of particle physics, which scientists use to explain elementary particles and their interactions, has so far not provided an answer to why the Universe did not collapse following the Big Bang,” said co-author Prof Arttu Rajantie of Imperial College London.

“Our research investigates the last unknown parameter in the Standard Model – the interaction between the Higgs particle and gravity.”

This parameter cannot be measured in particle accelerator experiments, but it has a big effect on the Higgs instability during inflation. Even a relatively small value is enough to explain the survival of the Universe without any new physics!”

The physicists plan to continue their research using cosmological observations to look at this interaction in more detail and explain what effect it would have had on the development of the early Universe.

In particular, they will use data from current and future ESA’s missions measuring cosmic microwave background radiation and gravitational waves.

“Our aim is to measure the interaction between gravity and the Higgs field using cosmological data,” Prof Rajantie said.

“If we are able to do that, we will have supplied the last unknown number in the Standard Model of particle physics and be closer to answering fundamental questions about how we are all here.”

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M. Herranen et al. 2014. Spacetime Curvature and the Higgs Stability During Inflation. Phys. Rev. Lett. 113, 211102; doi: 10.1103/PhysRevLett.113.211102