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We report the study¹ on the thermal properties of unparticle, a scale invariant sector with a non-trivial infrared fixed point. Unparticle with scaling dimension has peculiar thermal properties due to its unique phase space structure. We find that the equation of state parameter , the ratio of pressure to energy density, is given by providing a new form of energy in our universe. In an expanding universe, the unparticle energy density evolves dramatically differently from that for photons, which makes it possible to have a large unparticle relic density today.

The unparticle field operator can be expanded in terms of creation and destruction operators corresponding to particles with a continuous mass spectrum. Hence, when the four-momentum of an unparticle is measured, then the unparticle manifests as an ordinary particle with a definite (but arbitrary) mass.

Here we consider the case of primary scalar unparticle contributions to B_{d, s} mixing. With particular emphasis on the impact of the recent hint of new physics in the measurement of the B_s mixing phase, ϕ_s, we determine the allowed parameter space and impose bounds on the unparticle couplings.

We investigate the lepton flavor violation decays of vector mesons in the scenario of the unparticle physics by considering the constraint from μ-e conversion. In unparticle physics, the predictions of LFV decays of vector mesons depend strongly on the scale dimension . The predictions of LFV decays of vector mesons can reach the detective sensitivity in experiment in region of , while the prediction of μ-e conversion rate can meet the experimental upper limit. For the searching of the lepton flavor violation processes of charged lepton sector in experiment, the process ϒ→eμ may be a promising one to be observed.

The possible emergence of unparticle has been mooted recently including a mass-like term for gauge field with the Schwinger model at the classical level. A one-loop correction due to bosonization is taken into account and investigation is carried out to study its effect on the unparticle scenario. It is observed that the physical mass, viz., unparticle scale acquires a new definition, i.e. the effect of this correction enters into the unparticle scale in a significant manner. The fermionic propagator is calculated which also agrees with the new scale. It has also been noticed that a novel restoration of the lost gauge invariance reappears when the ambiguity parameter related to the current anomaly acquires a specific expression. We have also observed that a quantum effect can nullify the effect of violation of gauge symmetry caused by some classical terms.

The concept of exact and broken scale invariance is discussed. We give a brief introduction to unparticle physics. The neutral meson mixing can be caused by exchange of unparticle at the tree level. The constraints on interaction between unparticle and SM quarks are discussed.

We study the charged lepton electric dipole moment which is induced by the scalar unparticle mediation and we predict the appropriate range for the free parameters appearing in the effective Lagrangian which drives the unparticle-standard model lepton interactions. We observe that the charged lepton electric dipole moment is strongly sensitive to the scaling dimension d_u of the unparticle and the new couplings in the effective interaction. Furthermore, we see that the current experimental limits of charged lepton electric dipole moments can ensure an appropriate range for these free parameters.

Most signatures of new physics have been studied on the transverse plane with respect to the beam direction at the LHC where background is much reduced. In this paper we propose the analysis of inclusive longitudinal (pseudo)rapidity correlations among final-state (charged) particles in order to search for (un)particles belonging to a hidden sector beyond the Standard Model, using a selected sample of p–p minimum bias events (applying appropriate off-line cuts on events based on, e.g. minijets, high-multiplicity, event shape variables, high-p_⊥ leptons and photons, etc.) collected at the early running of the LHC. To this aim, we examine inclusive and semi-inclusive two-particle correlation functions, forward–backward correlations, and factorial moments of the multiplicity distribution, without resorting to any particular model but under very general (though simplifying) assumptions. Finally, motivated by some analysis techniques employed in the search for quark–gluon plasma in heavy-ion collisions, we investigate the impact of such intermediate (un)particle stuff on the (multi)fractality of parton cascades in p–p collisions, by means of a Lévy stable law description and a Ginzburg–Landau model of phase transitions. Results from our preliminary study seem encouraging for possible dedicated analyses at LHC and Tevatron experiments.

The virtual effects of unparticle physics on the two-gluon jets production are explored for CERN LHC. It is found that depending on the scale dimension, unparticles can give rise to substantial enhancements in the transverse momentum and pseudorapidity distributions of hadronic cross-sections, up to a factor of four-orders of magnitude.

Phenomenology of unparticle physics at linear as well as hadron colliders was briefly reviewed in this talk, including real emissions and virtual exchanges of unparticle. Existing constraints from collider as well as astrophysics experiments were briefly discussed.

We study the impact of unparticle physics to the chromomagnetic dipole moment (CMDM) of the top quark. We compute the effect induced by unparticle operators of scalar and vector nature coupled to fermions on the CMDM. We find that this dipole moment is sensitive to the scale dimensions d_u of the unparticle and the new couplings of the respective effective operators. Using the bounds imposed on the CMDM by low-energy precision and Tevatron measurements we derive indirect limits on the unparticle parameter space. In particular, we find that the scalar-unparticle operator contribution fulfills both constraints for most of the unparticle parameter space, while the low-energy precision bound on the CMDM excludes a vector-unparticle contribution for low values of respective scale dimension d_u.

In an exact conformal theory there is no particle. The excitations have continuum spectra and are called "unparticles" by Georgi. We consider supersymmetric extensions of the Standard Model with approximate conformal sectors. The conformal symmetry is softly broken in the infrared which generates a gap. However, the spectrum can still have a continuum above the gap if there is no confinement. Using the AdS/CFT correspondence this can be achieved with a soft wall in the warped extra dimension. When supersymmetry is broken the superpartners of the Standard Model particles may simply be a continuum above gap. The collider signals can be quite different from the standard supersymmetric scenarios and the experimental searches for the continuum superpartners can be very challenging.

In an exact conformal theory there is no particle. The excitations have continuum spectra and are called "unparticles" by Georgi. We consider supersymmetric extensions of the Standard Model with approximate conformal sectors. The conformal symmetry is softly broken in the infrared which generates a gap. However, the spectrum can still have a continuum above the gap if there is no confinement. Using the AdS/CFT correspondence this can be achieved with a soft wall in the warped extra dimension. When supersym-metry is broken the superpartners of the Standard Model particles may simply be a continuum above gap. The collider signals can be quite different from the standard supersymmetric scenarios and the experimental searches for the continuum superpartners can be very challenging.

We discuss various aspects of Conformal Field Theories on the Lattice. We mainly investigate the SU(3) gauge theory with N_f degenerate fermions in the fundamental representation, employing the one-plaquette gauge action and the Wilson fermion action.

First we make a brief review of our previous works on the phase structure of lattice gauge theories in terms of the gauge coupling constant and the quark mass. We thereby clarify the reason why we conjecture that the conformal window is 7 ≤ N_f ≤ 16.

Secondly, we introduce a new concept, “conformal theories with IR cutof” and point out that any numerical simulation on a lattice is bounded by an IR cutoff ∧_IR. Then we make predictions that when N_f is within the conformal window, the propagator of a meson G(t) behaves at large t, as G(t) = c exp (−m_Ht)/t^α, that is, a modified Yukawa-type decay form, instead of the usual exponential decay form exp (−m_Ht), in the small quark mass region. This holds on an any lattice for any coupling constant g, as far as g is between 0 and g*, where g* is the IR fixed point. We verify that numerical results really satisfy the predictions for the N_f = 7 case and the N_f = 16 case.

Thirdly, we discuss small number of flavors (N_f = 2 ∼ 6) QCD at finite temperatures. We point out theoretically and verify numerically that the correlation functions at T/T_c > 1 exhibit the characteristics of the conformal function with IR cutoff, an exponential decay with power correction.

Investigating our numerical data by a new method which we call the “local-analysis” of propagators, we observe that the N_f = 7 case and the N_f = 2 at T ∼ 2T_c case are similar to each other, while the N_f = 16 case and the N_f = 2 at T = 10² ∼ 10⁵T_c cases are similar to each other.

Further, we observe our data are consistent with the picture that the N_f = 7 case and the N_f = 2 at T ∼ 2T_c case are close to the meson unparticle model. On the other hand, the N_f = 16 case and the N_f = 2 at T = 10² ∼ 10⁵T_c cases are close to a free state in the Z(3) twisted vacuum. All results are consistent with naive physical intuition and give clues for long standing issues at high temperatures such as why the free energy at high temperatures does not reach the Stefan-Boltzmann ideal gas limit even at T = 100T_c.