Probing universal extra dimension at the international linear collider

We consider the UED scenario and study the detectability of the first KK electron-positron pair at the ILC. A few hundred GeV KK electron decays into a nearly degenerate KK photon, which carries away missing energy, and the standard electron. The mass splitting between the KK electron and KK photon is controlled by the bulk-and brane-induced radiative corrections. We look for the signal event e ⁺ e ⁻ + large missing energy for √s = 1 TeV and observe that with a few hundred fb⁻¹ luminosity the signal can be deciphered from the standard model background. We briefly outline how the UED signals may be distinguished from the supersymmetric signals. This talk is based on a work the author did with Paramita Dey, Anirban Kundu and Amitava Raychaudhuri [1].     

Signals of universal extra dimension at the international linear collider

In the minimal universal extra dimension model, single production of n = 2 gauge bosons provides a unique discriminating feature from supersymmetry. We discuss how the proposed international linear collider can act as a n = 2 factory, much in the same vein as LEP.      

Consistent ADD scenario with stabilized extra dimension

A model with one compact extra dimension and a scalar field of Brans–Dicke type in the bulk is discussed. It describes two branes with non-zero tension embedded into the space-time with flat background. This setup allows one to use a very simple method for stabilization of the size of extra dimension. It appears that the four-dimensional Planck mass is expressed only through parameters of the scalar field potentials on the branes.     

l i → l jγ decays within a model involving a universal extra dimension

Flavor-changing radiative lepton decays of the l _i → l _jγ type are studied within a model involving a universal extra dimension. Loop amplitudes where intermediate fermions and scalar bosons have commensurate masses may be quite large since the quadratic suppression factor reduces to a linear one in this case. The situation where fermions and scalar bosons have commensurate masses in a loop is realized in a model featuring universal extra dimensions. The contribution of Kaluza—Klein towers to the l _i → l _jγ decay amplitude is explicitly calculated. However, the enhancement expected in the amplitude on the basis of general considerations disappears because of the maximal degeneracy of massive-neutrino tower modes associated with different generations.     

Multisupergravity from latticized extra dimension

The construction of the linearized four-dimensional multisupergravity from five-dimensional linearized supergravity with discretized fifth dimension is presented. The one-loop vacuum energy is evaluated when (anti)periodic boundary conditions are chosen for (bosons) fermions, respectively, or vice versa. It is proposed that the relation between discretized M-theory and strings may be found in the same fashion.     

Quantum simulation of an extra dimension

We present a general strategy to simulate a D+1-dimensional quantum system using a D-dimensional one. We analyze in detail a feasible implementation of our scheme using optical lattice technology. The simplest nontrivial realization of a fourth dimension corresponds to the creation of a bi-volume geometry. We also propose single- and many-particle experimental signatures to detect the effects of the extra dimension.     

Two-photon decays of neutral <Emphasis Type="Italic">B</Emphasis> mesons within a model featuring one universal extra dimension

Contributions to the B _s(d) → γγ decay amplitude beyond the Standard Model are estimated within a model featuring one universal extra dimension. It is found that these additional contributions may amount to 6 or 7% of the branching ratios evaluated within the Standard Model.     

A bound on universal extra dimension models from up to 2 fb of LHC data at 7 TeV

The recent up to ∼2 fb−1 of data from the ATLAS and CMS experiments at the CERN Large Hadron Collider at 7 TeV put an upper bound on the production cross section of a Higgs-like particle. We translate the results of the H→WW→lνlν and H→γγ as well as the combined analysis by the ATLAS and CMS into an allowed region for the Kaluza-Klein (KK) mass MKK and the Higgs mass MH for all the known Universal Extra Dimension (UED) models in five and six dimensions. Our bound is insensitive to the detailed KK mass splitting and mixing and hence complementary to all other known signatures.     

The border model in one dimension

The magnetic susceptibility is studied by the methods of series analysis for the one-dimensional border model (a special case of the continuous-spin Ising model). The structure of this model is analyzed and two conjugate pairs of singularities are found near the real (physical) temperature axis. All the numerical results are consistent with the previously known rigorous results, but do not add to the knowledge of the critical properties.     

Higgs production via gluon fusion in a six-dimensional universal extra dimension model on S 2/Z 2

We investigate Higgs boson production process via gluon fusion at LHC in our six-dimensional universal extra dimension model compactified on a spherical orbifold S ²/Z ₂. We find a striking result that the Higgs production cross section in our model is predicted to have 30(10)% enhancement compared to the predictions of the Standard Model (the minimal universal extra dimension model) for the compactification scale of order 1 TeV.     

B-factory signals for a warped extra dimension

We study predictions for B physics in a class of warped extra dimension models recently introduced, where few ( approximately 3) TeV Kaluza-Klein masses are consistent with electroweak data due to custodial symmetry. As in the standard model (SM), flavor violations arise due to the heavy top quark leading to striking signals: (i) New physics contributions to DeltaF=2 transitions are comparable to the SM, so the success of the SM unitarity triangle fit is a "coincidence." Thus, clean extractions of unitarity angles are likely to be affected, in addition to O(1) deviation from the SM prediction in B(s) mixing. (ii) O(1) deviation from various SM predictions for B-->X(s)l(+)l(-). (iii) Large mixing-induced CP asymmetry in radiative B decays. Also, the neutron electric dipole moment is roughly 20 times larger than the current bound so that this framework has a "CP problem."     

Fisher equation with turbulence in one dimension

As an example of life at high Reynolds number, we investigate the dynamics of the Fisher equation for the spreading of micro-organisms in one dimension subject to both turbulent convection and diffusion. We show that for strong enough turbulence, bacteria, for example, track, in a quasilocalized fashion (with remarkably long persistence times), sinks in the turbulent field. An important consequence is a large reduction in the carrying capacity of the fluid medium. We analytically determine the regimes where this quasi-localized behavior occurs and test our predictions by numerical simulations.     

The generalized point interaction in one dimension

We show that various self-adjoint extensions of the operatorH ₀ ⁰ =–d²/dx²,D(H ₀ ⁰ )= =C (R{o}) describes a particle moving under additional influence of the generalized Fermi pseudopotential.I am indebted to Dr. H. Englisch for stimulating discussions. I am also grateful to the Department of Mathematics at the Karl-Marx-Universität Leipzig where this work was done.     

Search for universal extra dimensions in pp collisions

We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions (UED) using a data set corresponding to an integrated luminosity of 7.3 fb(-1), collected by the D0 detector at a pp center-of-mass energy of 1.96 TeV. The decay chain of KK particles can lead to a final state with two muons of the same charge. This signature is used to set a lower limit on the compactification scale of R(-1)>260 GeV in a minimal UED model.     

CKM pattern from localized generations in extra dimension

We revisit the issue of the quark masses and mixing angles in the framework of large extra dimension. We consider three identical standard model families resulting from higher-dimensional fields localized on different branes embedded in a large extra dimension. Furthermore we use a decaying profile in the bulk different form previous works. With the Higgs field also localized on a different brane, the hierarchy of masses between the families results from their different positions in the extra space. When the left-handed doublet and the right-handed singlets are localized with different couplings on the branes, we found a set of brane locations in one extra dimension which leads to the correct quark masses and mixing angles with the sufficient strength of CP-violation. We see that the decaying profile of the Higgs field plays a crucial role for producing the hierarchies in a rather natural way.