Higgs inflation after the BICEP2 & Planck results

Seong Chan Park (SKKU & KIAS)

The 4th KIAS workshop on Particle Physics and Cosmology, 27-31 Oct. 2014

1. Higgs inflation is still alive by Yuta Hamada, Hikaru Kawai, Kin-ya Oda, and SCP, Phys. Rev. Lett. 112 241301 (2014)arXiv:1403.5043

2. Higgs inflation from Standard Model criticality by the same authorsarXiv:1408.4864 for full analysis

Refs

Disclaimer noteAfter excellent talks on the related topics in the morning session, I may add a little more information.

However, I found it always pleasure to hear something that I already know about. So I hope you enjoy my talk, too.

Also, I would describe what I could see as a particle phenomenologist which may be useful for some people in audience.

Disclaimer note 2I assume:

SM is good to Planck scale, which is unlikely. But, as long as corrections are by weak (gauge) interactions or higher loops, their effects are subdominant anyway. Higher order operators are suppressed even though some non-zero contribution (~10-9) actually helps to fit the running of spectral index.

A key message today

We may learn about LHC physics from cosmological data in Higgs inflation!

Higgs inflationAn economical and predictive idea : Higgs=Inflaton

at low scale (~100 GeV) responsible for EWSB

at high scale (~1017 GeV) responsible for cosmic inflation

See Bezrukov’s talk

50 100 150 200 250 300 350

2×108

4×108

6×108

8×108

Higgs potential

e.g., precise measurement of top quark mass

may be achievable in “Higgs inflation”

This is not a small thing!

CMS PAS TOP-14-001

Current top quark mass measurement

NEWJuly!2014!

[CMS!PAS!TOP-14-002]

Mt=175->173->172 Error remains still big~GeVTo reduce the error, one should have better understanding of “MC mass” but this is tough in LHC!ILC ‘scan’ around 350 GeV allows ∆Mt=100 MeV…

Higgs in the SM• A scalar field (s=0) (2,1/2) of

: “doublet”

• Tachyonic, develops non-zero VEV

• two free parameters in the general renormalizable action

Higgs in the SM• W-mass and gauge

coupling measurement or equivalently GF :

• from the LHC!

Now, the parameters in the Higgs sector

are experimentally measured!

CMS PAS HIG-14-009

ATLAS arXiv:1406.3827

PDG new

Current status of Higgs mass measurement

CMS PAS HIG-14-009

Decay pattern is consistent with the SM!

The Higgs in the SM plays two main roles: EWSB (or gauge boson masses) and fermion masses. Both have been experimentally checked!

Yuta Takahashi’s talk@KEK-ph2014

Inflation solves problemInflation is exponential expanding stage of Universe in an early era

gives chance to have causal connection in “our patch of universe” Then, homogeneity, isotropy and no observation of monopole, domain wall etc are explained.

also provides seed for structure formation provided.

Era of inflationspace inflates > e60

space

time

our “patch”

In particle physics, inflation takes place due to a scalar particle

This is what we want:

This is the equation:

“slow-roll conditions”It is realized if the potential is “flat”

(ex)N.B. This guy is scalaror a composite state with s=0.

Q. WHY?

Higgs vs Inflaton

Chaotic InflationHiggs

look very different…

But! The Higgs potential becomes flat at high scale by RGE!

The SM Higgs quartic coupling

2-loop effective potential

criticality

arXiv:1405.4781

[Hamada, Kawai, Oda, SCP, PRL 2014]

Criticality of the SM

+loop

[Hamada, Kawai, Oda, SCP, 1403.5043, PRL], [Bezrukov, Shaposhinikov, 1403.6078]

% of woman science major

Criticality of the SM

+loop

Plateau!This helps.

But, not enough for 60 efoldings.

[Hamada, Kawai, Oda, SCP, PRL 2014]

Another source of flatness:“non-minimal coupling”

Generically allowed in SUGRA.In effective theory, this term should be included

as long as

“Inflation by non-minimal couplings”[SCP, S.Yamaguchi (2008)]

Thus, as long as V/K2 is asymptotically flat, the slow-roll inflation can take place!

(ex) monomial

An interesting topic for model building

Origin???

m=2 “Higgs Inflation” [Bezrukov,Shaposhinikov (2008)]

(ex) monomial

COBE normalization:

(hard to swallow…)

At low scale, Higgs potential with/without non-minimal coupling term look just same.

consistent with the low energy measurements!

GeV

two plots!

At high scale, the potential becomes flat with NMC:

non-minimal

minimal

good for inflation!

Two (and more) cosmological observables

“Scalar spectral Index”

“scale invariance”

“Tensor-to-scalar ratio”

“how fast?”

( also running spectral index, Non-Gaussianity etc…)

Tensor-to-scalar ratio is seen in

“B-mode” polarization in CMBR

Any massless field experiences quantum fluctuations during inflation:gravitational field too.

There are two polarization modes of a gravitational wave:

Helmholtz theoremcurl-freedivergence freeNot

surprisin

g!

BICEP2

r~how fast the inflaton moves ~the slope in

potential

w/o foreground noise

-Foreground dust must be better understood!

1405.7351 by Faluger, Hill and Spergel

Also, “astro-5 sigmas” often disappear (rate~50%)

Planck intermediate results. XXX.arXiv:1409.5738

Planck showed that the power spectrum indicates that the uncertainty is comparable in magnitude to the

BICEP2 measurements at these multipoles.

Assessing the dust contribution to the B-mode power measured by the BICEP2 experiment requires a dedicated joint analysis with Planck, incorporating all pertinent observational details of the two data sets, such as masking, filtering, and color corrections. (Further analysis is needed to rule out any sign of B-Mode observation by BICEP2.)

[SCP, S.Yamaguchi (2008)]

n is around 0.965r is expected to be ‘small’~0.003 !

W/O RGE

Higgs Inflation w/o RGE=R2 inflation

Higgs inflation=R2 inflation

“Higgs”

“R2”

[COBE]

w/ RGE

larger NM coupling

[Hamada, Kawai, Oda, SCP, PRL 2014]

Higgs inflation w/ RGE, criticality”

“higher orderterms”

negative running

Mt in Higgs Inflation

summaryBICEP + Planck, if confirmed, fantastic!! If not, we will learn more about dust any way. Higgs may play a role of inflaton and Higgs inflation is compatible with data: n=0.967 and r=0.003 or ~0.1 wo/w criticality. (greater possibility is open for Higgs inflation with criticality) With criticality (r~0.1), Mt may be (best) measured by cosmological data! PLANCK and BICEP upgrades(BICEP3, KECK array) result will tell us more. Let’s stay tuned.

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Thank you!