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B. Grzadkowski J.W

UN. - cosmology. B. Grzadkowski J.W. UV completion. Banks-Zaks ( BZ ) phase Asymptotically free. New physics. Standard Model. Unparticle ( U ) phase Conformally invariant. Basic idea. New type of physics such that It is conformally invariant in the IR Asymptotically free in the UV

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B. Grzadkowski J.W

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  1. UN - cosmology B. Grzadkowski J.W

  2. UV completion Banks-Zaks (BZ) phase Asymptotically free New physics Standard Model Unparticle (U) phase Conformally invariant Basic idea • New type of physics such that • It is conformally invariant in the IR • Asymptotically free in the UV • It interacts weakly with the SM Heavy Mediators

  3. The new physics sector has two relevant scales: The history of unparticles is dark and unknown but it is nevertheless divided by theoreticians into three periods The first about which we know nothing The second about which we know almost as much as about the first And the third which succeeded the first two (with apologies to A. Averchenko) UV completion BZ phase Unparticle phase

  4. To make calculations one needs: That follows from conformal invariance Rather unique collider signatures No experimental motivation whatsoever Can be used to understand how unusual types of new physics can affect cosmic evolution

  5. g* g* Thermodynamics • Conformal invariance: •  has a non-trivial IR zero at g=g* • The trace of the energy momentum tensor vanishes in the IR = anomalous dimension of F2

  6. In the UV: asymptotically free )/ T4 to leading order ) For available models gNP» 100

  7. SM-NP interactions Equilibrium, freeze-out and thaw-in Standard approach: use the Boltzmann equation Equilibrium as long as  > H = H at T = Tf Less standard approach: use the Kubo equation … yields the same result … but does not need to introduce the unparticle distribution function

  8. NP SM’ Energy = ENP 4-momentum=KNP Energy = E’NP 4-momentum=K’NP Energy = E 4 mom. = K Energy = E’ 4 mom. = K’ SM Energy = ESM 4-momentum=KSM Energy = E’SM 4-momentum=K’SM NP’

  9. Only need a order of magnitude estimate for :

  10. > H: coupled < H: decoupled ' H ) T = Tf dSM + dNP > 4.5 ) freeze-out dSM + dNP < 4.5 ) thaw-in

  11. We assume that SP and NP were in equillibrium as T !1 SN-NP coupling/decoupling Blue: Tf2U phase Red: SM-NP coupled No-color: Tf < v

  12. Unparticle effects on BBN If SM-NP were in equilibrium and then decoupled, TSM and TNP can be related using entropy conservation:

  13. NP contribution to  mimics that of additional ’s If SM-NP remain in equilibrium during BBN: gIR < 0.3 So unparticle models should exhibit conformal invariance with a small number of RDF in the IR. Unaware of an explicit model with this property

  14. Comments Strongly coupled new physics can lead to /H » Tn (n positive or negative) ) A variety o freeze-out and thaw-in scenarios are viable ) BBN generates strong constraints on the NP. Even for the “normal” decoupling scenarios (n>0) the BBN constraint is significant: gIR < 20, while the models available have gIR > 100 Unparticle models also suffer from potential theoretical problems: the coupling to the SM necessarily breaks conformal invariance. If this effect is strong the above arguments do not apply … but then the experimental signatures are particle-like

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