Articles de revues : « Randall-Sundrum (RS) Model »

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Wulandari, Dewi, Triyanta, Jusak S. Kosasih, Douglas Singleton et Preston Jones. « Localization of interacting fields in five-dimensional braneworld models ». International Journal of Modern Physics A 32, n^o 32 (20 novembre 2017) : 1750191. http://dx.doi.org/10.1142/s0217751x17501913.

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We study the localization properties of fundamental fields which are coupled to one another through the gauge mechanism both in the original Randall–Sundrum (RS) and in the modified Randall–Sundrum (MRS) braneworld models: scalar–vector, vector–vector, and spinor–vector configuration systems. For this purpose, we derive conditions of localization, namely, the finiteness of integrals over the extra coordinate in the action of the system considered. We also derive field equations for each of the systems and then obtain their solutions corresponding to the extra dimension by a separation of variable method for every field involved in each system. We then insert the obtained solutions into the conditions of localization to seek whether or not the solutions are in accordance with the conditions of localization. We obtain that not all of the configuration systems considered are localizable on the brane of the original RS model while, on the contrary, they are localizable on the MRS braneworld model with some restrictions. In terms of field localizability on the brane, this result shows that the MRS model is much better than the original RS model.

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Kobakhidze, Archil, Kristian L. McDonald, Lei Wu et Jason Yue. « Warped graviton couplings to bulk vectors with brane-localized kinetic terms ». International Journal of Modern Physics A 32, n^o 33 (30 novembre 2017) : 1745004. http://dx.doi.org/10.1142/s0217751x1745004x.

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In this paper, we realize nonuniversal couplings between Kaluza–Klein (KK) gravitons and bulk Standard Model (SM) vectors in the Randall–Sundrum (RS) model by including both UV and IR brane-localized gauge kinetic terms. We find that such kinetic terms can reduce the couplings of KK gravitons to SM gauge bosons and also ensure the KK vector masses are consistent with electroweak precision constraints.

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Jawad, Abdul, Sabir Hussain, Shamaila Rani et Saba Qummer. « Generalized ghost Tsallis holographic dark energy model in RS-II braneworld and dynamical Chern-Simons modified gravity ». International Journal of Geometric Methods in Modern Physics 17, n^o 08 (juillet 2020) : 2050124. http://dx.doi.org/10.1142/s0219887820501248.

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In this paper, we studied the cosmological implications of generalized ghost Tsallis holographic dark energy in the framework of Randall–Sundrum II braneworld and Chern–Simons modified gravity in flat FRW universe. We discuss the cosmological parameters like equation of state parameter, deceleration parameter, squared speed of sound, Om-diagnostic and planes like evolving equation of state parameter and statefinders. These models yield useful results in this context.

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COGNOLA, GUIDO, SERGIO ZERBINI, EMILIO ELIZALDE, SHIN'ICHI NOJIRI et SERGEI D. ODINTSOV. « MULTI-GRAVITON THEORY FROM A DISCRETIZED RS BRANE-WORLD AND THE INDUCED COSMOLOGICAL CONSTANT ». Modern Physics Letters A 19, n^o 19 (21 juin 2004) : 1435–45. http://dx.doi.org/10.1142/s0217732304014148.

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We propose a multi-graviton theory with non-nearest-neighbor couplings in the theory space. The resulting four-dimensional discrete mass spectrum reflects the structure of a latticed extra dimension. For a plausible mass spectrum motivated by the discretized Randall–Sundrum brane-world, the induced cosmological constant turns out to be positive and may serve as a quite simple model for the dark energy of our accelerating universe.

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NOZARI, KOUROSH, et M. SHOUKRANI. « NON-MINIMAL INFLATION ON THE RANDALL–SUNDRUM II BRANE WITH INDUCED GRAVITY ». Modern Physics Letters A 24, n^o 39 (21 décembre 2009) : 3205–17. http://dx.doi.org/10.1142/s0217732309031132.

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We study an inflation model that inflaton field is non-minimally coupled to the scalar curvature on the Randall–Sundrum (RS) II brane. We investigate the effects of the non-minimal coupling on the inflationary dynamics of this braneworld model. Our study shows that the number of e-folds decreases by increasing the value of the conformal coupling. We compare our model parameters with the minimal case and also with recent observational data. In comparison with recent observation, we obtain a constraint on the values that conformal coupling attains.

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Videla, Nelson, et Grigorios Panotopoulos. « Natural Inflation on the brane with a TeV-scale gravity : Parameter constraints after Planck 2015 ». International Journal of Modern Physics D 26, n^o 07 (26 décembre 2016) : 1750066. http://dx.doi.org/10.1142/s0218271817500663.

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In the present work, we have studied Natural Inflation (NI) in the framework of the Randall–Sundrum II (RS-II) brane model in the light of the latest Planck results. Adopting the Randall–Sundrum fine-tuning, the model is characterized by three parameters in total, namely the five-dimensional (5D) Planck mass [Formula: see text] and the two mass scales of the inflaton potential [Formula: see text] and [Formula: see text]. We show in the [Formula: see text]–[Formula: see text] plane the theoretical predictions of the model together with the allowed contour plots, and we conclude that the model is viable. By using the Planck results only, it is possible to determine the two mass scales of the inflaton potential in terms of [Formula: see text], which remains undetermined. However, there are several good theoretical reasons to consider a higher-dimensional Planck mass of the order of [Formula: see text][Formula: see text]TeV, which is compatible with primordial nucleosynthesis. If we insist on considering a [Formula: see text] of this order of magnitude, all parameters are known and a sub-Planckian excursion of the inflaton scalar field is achieved.

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de Anda, Francisco J. « Left–right model from gauge-Higgs unification with dark matter ». Modern Physics Letters A 30, n^o 12 (6 avril 2015) : 1550063. http://dx.doi.org/10.1142/s0217732315500637.

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We propose a five-dimensional model based on the idea of Gauge-Higgs Unification (GHU) with the gauge group SO(5) × U(1) in Randall–Sundrum (RS) spacetime. We obtain a left–right (LR) symmetric model with a stable scalar identified as a dark matter candidate. This stable scalar obtains a vacuum expectation value (VEV) that gives mass to fermions in the bulk through the Hosotani Mechanism. There is a scalar localized on a brane and gives contributions to fermion masses. This scalar fits the observed Higgs boson data. We are able to fit all the Standard Model (SM) observables while evading constraints.

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Soa, Dang Van, et Bui Thi Ha Giang. « The influence of the scalar unparticle on the W-pair production at ILC in the Randall–Sundrum model ». Modern Physics Letters A 35, n^o 25 (25 juin 2020) : 2050217. http://dx.doi.org/10.1142/s021773232050217x.

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An attempt is made to present the contribution of the scalar unparticle on some scattering processes in the Randall–Sundrum (RS) model. We have evaluated the contribution of the scalar unparticle on the W-pair production cross-sections at International Linear Colliders (ILC). The results indicate that at the low values of the scaling dimension and the bounds on scale [Formula: see text] are around few TeV, the cross-sections are much enhanced, which is quite comparable with the W-production in the Standard Model and hence it is worthwhile to explore in future colliders.

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CHO, Y. M., et I. P. NEUPANE. « WARPED BRANE-WORLD COMPACTIFICATION WITH GAUSS–BONNET TERM ». International Journal of Modern Physics A 18, n^o 15 (20 juin 2003) : 2703–27. http://dx.doi.org/10.1142/s0217751x03015106.

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In the Randall–Sundrum (RS) brane-world model a singular delta-function source is matched by the second derivative of the warp factor. So one should take possible curvature corrections in the effective action of the RS models in the Gauss–Bonnet (GB) form. We present a linearized treatment of gravity in the RS brane-world with the Gauss–Bonnet modifications to Einstein gravity. We give explicit expressions for the Neumann propagator in arbitrary D dimensions and show that a bulk GB term gives, along with a tower of Kaluza–Klein modes in the bulk, a massless graviton on the brane, as in the standard RS model. Moreover, a nontrivial GB coupling can allow a new branch of solutions with finite Planck scale and no naked bulk singularity, which might be useful to avoid some of the previously known "no-go theorems" for RS brane-world compactifications.

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Debnath, Partha Sarathi. « Observational constraints of emergent universe in brane-world with Gauss–Bonnet term and dissipative effect ». International Journal of Geometric Methods in Modern Physics 16, n^o 11 (novembre 2019) : 1950169. http://dx.doi.org/10.1142/s021988781950169x.

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Cosmological solutions in the Randall–Sundrum (RS) type II brane-world model including Gauss–Bonnet (GB) term, in the presence of a bulk viscous cosmological fluid are discussed. Transport equations described by Eckart and Israel Stewart are implemented here. Cosmological models admitting emergent universe (EU) of the early universe is explored here in the presence of imperfect fluid described by Eckart theory and Truncated Israel Stewart (TIS) theory and Full Israel Stewart (FIS) theory. We also study the permitted values of the EU model parameters by considering cosmological observational dataset. The stability analysis of the equilibrium points of the dynamical system associated with the evolution in the RS brane including GB term are studied in Eckart theory, TIS theory and FIS theory.

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SOA, D. V., D. T. L. THUY, N. H. THAO et T. D. THAM. « RADION PRODUCTION IN γe- COLLISIONS ». Modern Physics Letters A 27, n^o 23 (24 juillet 2012) : 1250126. http://dx.doi.org/10.1142/s021773231250126x.

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We analyze the potential of Compact Linear Colliders (CLIC) based on the γe- collisions to search for the radion in the Randall–Sundrum (RS) model, where compactification radius of the extra dimension is stabilized by the radion, which is a scalar field lighter than the graviton Kaluza–Klein states. The radion production in high energy γe- colliders with the polarization of the electron beams are calculated in detail. Numerical evaluation shows that if the radion mass is not too heavy with the mass order of GeV, then the reaction can give observable cross-section in future colliders at the high degree of polarization.

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Cuspinera, Leopoldo, Ruth Gregory, Katie M. Marshall et Ian G. Moss. « Higgs vacuum decay in a braneworld ». International Journal of Modern Physics D 29, n^o 01 (4 décembre 2019) : 2050005. http://dx.doi.org/10.1142/s0218271820500054.

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We examine the effect of large extra dimensions on vacuum decay in the Randall–Sundrum (RS) braneworld paradigm. We assume the scalar field is confined to the brane, and compute the probability for forming an “anti-de Sitter” (AdS) bubble inside a critical flat RS brane. We present the first full numerical solutions for the brane instanton considering two test potentials for the scalar field. We explore the geometrical impact of thin and thick bubble walls, and compute the instanton action in a range of cases. We conclude by commenting on a more physically realistic potential relevant for the Standard Model Higgs. For bubbles with large backreaction, the extra dimension has a dramatic effect on the tunnelling rate, however, for the weakly backreacting bubbles more relevant for realistic Standard Model potentials, the extra dimension has little impact.

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KIM, KYONG HEE, et YUN SOO MYUNG. « TEST OF PATCH COSMOLOGY WITH WMAP ». International Journal of Modern Physics D 14, n^o 10 (octobre 2005) : 1813–29. http://dx.doi.org/10.1142/s0218271805007425.

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We calculate the power spectrum, spectral index, and running spectral index for inflationary patch cosmology arisen from Gauss–Bonnet braneworld scenario using the Mukhanov equation. This patch cosmology consists of Gauss–Bonnet (GB), Randall–Sundrum (RS-II), and four-dimensional (4D) cosmological models. There exist several modifications in higher order calculations. However, taking the power-law inflation by choosing different potentials depending on the model, there exist minor changes up to second order corrections. Since second order corrections are rather small in the slow-roll limit, we could not choose a desired power-law model which explains the WMAP data. Finally we discuss the reliability of high order calculations based on the Mukhanov equation by comparing the perturbed equation including 5D metric perturbations. It turns out that first order corrections are reliable, while second order corrections are not proved to be reliable.

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Abu-Ajamieh, Fayez. « The radion as a dark matter candidate ». International Journal of Modern Physics A 33, n^o 24 (30 août 2018) : 1850144. http://dx.doi.org/10.1142/s0217751x18501440.

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I study a class of Randall–Sundrum (RS) models with Spontaneous Breaking of Scale Invariance (SBSI). This class of models implements the Contino–Pomarol–Rattazzi (CPR) mechanism to achieve SBSI through the small running of an external close-to-marginal scale-breaking operator that leads to a light dilaton/radion with couplings to matter suppressed by the small running. I show that for radion masses [Formula: see text] KeV, it can serve as a dark matter (DM) candidate, with a lifetime longer than the age of the universe, and show that the experimental bounds from LHC, non-Newtonian gravity and Axion-Like Particle (ALP) searches allow for the existence of such a radion. In spite of the small relic abundance of the light radion produced in this model, we show that it could be possible to obtain the required abundance through additional assumptions, an issue we postpone to the future.

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Iyer, Abhishek M. « Flavour physics and extra-dimensions ». EPJ Web of Conferences 179 (2018) : 01006. http://dx.doi.org/10.1051/epjconf/201817901006.

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Randall-Sundrum (RS) model of warped extra-dimensions were originally proposed to explain the Planck-weak scale hierarchy. It was soon realised that modifications of the original setup, by introducing the fields in the bulk, has several interesting features. In particular it imbues a rich flavour structure to the fermionic sector thereby offering an understanding of the Yukawa hierarchy problem. This construction is also useful in explaining the recently observed deviations in the decay of the B mesons. We consider two scenarios to this effect : A) Right handed muon fields coupled more to NP that the corresponding muon doublets (unorthodox case). Non-universality exists in the right handed sector. B) Standard scenario with anomalies explained primarily by non-universal couplings to the lepton doublets. Further, we establish correlation with the parameter space consistent with the flavour anomalies in the neutral current sector and obtain predictions for rare K- decay which are likely to be another candle for NP with increased precision. The prediction for rare K- decays are different according to the scenario, thereby serving as a useful discriminatory tool. We also discussthe large flavour violation in the lepton sector and present an example with the implementation of bulk leptonic MFV which is essential to realize the model with low KK scales. Further we consider a radical solution, called GUT RS models, where the RS geometry can work as theory of flavour in the absence of flavour symmetries. In this case the low energy brane corresponds to the GUT scale as a result of which RS is no longer solution to the gauge hierarchy problem. The Kaluza Klein (KK) modes in this setup are naturally heavy due to which the low energy constraints can be easily avoided. We use this framework to discuss the supersymmetric version of the RS model and provide means to test this scenario by considering rare lepton decays like τ → μγ.

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Quiros, Mariano. « Higgs bosons in extra dimensions ». Modern Physics Letters A 30, n^o 15 (7 mai 2015) : 1540012. http://dx.doi.org/10.1142/s021773231540012x.

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In this paper, motivated by the recent discovery of a Higgs-like boson at the Large Hadron Collider (LHC) with a mass mH≃125 GeV , we review different models where the hierarchy problem is solved by means of a warped extra dimension. In the Randall–Sundrum (RS) model electroweak observables provide very strong bounds on the mass of KK modes which motivates extensions to overcome this problem. Two extensions are briefly discussed. One particular extension is based on the deformation of the metric such that it strongly departs from the AdS5 structure in the IR region while it goes asymptotically to AdS5 in the UV brane. This model has the IR brane close to a naked metric singularity (which is outside the physical interval) characteristic of soft-walls constructions. The proximity of the singularity provides a strong wave function renormalization for the Higgs field which suppresses the T and S parameters. The second class of considered extensions are based on the introduction of an extra gauge group in the bulk such that the custodial SU (2)R symmetry is gauged and protects the T parameter. By further enlarging the bulk gauge symmetry one can find models where the Higgs is identified with the fifth component of gauge fields and for which the Higgs potential along with the Higgs mass can be dynamically determined by the Coleman–Weinberg mechanism.

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Thuc, Le Nhu. « The The Bhabha Scattering in the Randall-sundrum Model ». VNU Journal of Science : Mathematics - Physics 34, n^o 4 (17 décembre 2018). http://dx.doi.org/10.25073/2588-1124/vnumap.4292.

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The change in other two fermion processes is called Bhabha process. In this paper, we discuss the Bhabha process in the Randall –Sundrum (RS). We caculated the cross section for photon , boson Z, radion and Higgs h exchange and evaluated exchange contributions of the Bhabha process in detail. Keywords: DCS, cross-section, Bhabha, radion, Randall-Sundrum. References [1] L. Randall and R. Sundrum, Phys. Rev. Lett. 83, 3370, 1999.[2] H. Davoudiasl, T. McElmurry and A. Soni, Phys. Rev. D82, 115028, 2010.[3] V. P. Goncalves and W. K. Sauter, Phys. Rev. D82, 056009, 2010. [4] W. -J. Zhang, W. -G. Ma, R. -Y. Zhang, X. -Z. Li, L. Guo, and C. Chen, Phys. Rev. D92, 116005, 2015, [arXiv:1512.01766].[5] C. Cai, Z.-H. Yu and H.-H. Zhang, Phys. Rev. D93. 075033, 2016.[6] F. Abu-Ajamieh, R. Houtz, and R. Zheng, [arXiv: 1607.01464v1 [hep-ph]], 2016.[7] The CMS Collaboration, CERN, August 2016.[8] The CMS Collaboration, CERN, September 2016.[9] F. Richard, [ arXiv:1804.02846 [hep-ex]], 2018.

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Bernal, Nicolás, Andrea Donini, Miguel G. Folgado et Nuria Rius. « FIMP Dark Matter in Clockwork/Linear Dilaton extra-dimensions ». Journal of High Energy Physics 2021, n^o 4 (avril 2021). http://dx.doi.org/10.1007/jhep04(2021)061.

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Abstract We study the possibility that Dark Matter (DM) is made of Feebly Interacting Massive Particles (FIMP) interacting just gravitationally with the Standard Model particles in the framework of a Clockwork/Linear Dilaton (CW/LD) model. We restrict here to the case in which the DM particles are scalar fields. This paper extends our previous study of FIMP’s in Randall-Sundrum (RS) warped extra-dimensions. As it was the case in the RS scenario, also in the CW/LD model we find a significant region of the parameter space in which the observed DM relic abundance can be reproduced with scalar DM mass in the MeV range, with a reheating temperature varying from 10 GeV to 109 GeV. We comment on the similarities of the results in both extra-dimensional models.

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Manglani, N., A. Misra et K. Sridhar. « KK Higgs produced in association with a top quark pair in the bulk RS model ». European Physical Journal C 79, n^o 11 (novembre 2019). http://dx.doi.org/10.1140/epjc/s10052-019-7487-8.

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AbstractWe present a search strategy for the first Kaluza–Klein (KK) mode of the Higgs boson in the framework of the Randall–Sundrum (RS) model with a deformed metric. We study the production of this massive excitation in association with a $$ t {\bar{t}}$$tt¯ pair at the large hadron collider (LHC). The KK Higgs primarily decays into a boosted $$t {\bar{t}}$$tt¯ final state and we then end up with an interesting four-top final state of which two are boosted. The boosted products in the final state improve the sensitivity for the search of the KK Higgs in this channel whose production cross-section is otherwise rather small. Our results suggest that masses of the KK Higgs resonance upto about 1.2 TeV may be explorable at the highest planned luminosities of the LHC. Beyond this mass, the KK Higgs cross-section is too tiny for it to be explored at the LHC and may be possible only at a future higher energy collider.

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Debnath, Partha Sarathi, Bikash Chandra Roy et Bikash Chandra Paul. « Hybrid expansion law in viscous braneworld gravity with Gauss–Bonnet terms ». Modern Physics Letters A 37, n^o 20 (28 juin 2022). http://dx.doi.org/10.1142/s0217732322501292.

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The cosmological model executing hybrid expansion law (HEL) of scale factor in Randall–Sundrum type II (RS) braneworld gravity with Gauss–Bonnet terms in the presence of bulk viscosity described by Eckart theory, Truncated Israel–Stewart (TIS) theory, Full Israel–Stewart (FIS) theory and nonlinear Israel–Stewart (nIS) theory is studied. In the hybrid expansion law, the scale factor of the universe is described by the product of power-law and exponential expansions. In the HEL model, the early inflation and its transition from deceleration phase to present accelerated phase of expansion can be explored. The constraints of hybrid expansion law model parameters are determined using the recent observational data. Thereafter, the estimated parameters are considered to explore the present value of deceleration parameter, jerk parameter and transition epoch from early deceleration to the present accelerating phase.

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Bhattacharya, Aranya, Arpan Bhattacharyya, Pratik Nandy et Ayan K. Patra. « Islands and complexity of eternal black hole and radiation subsystems for a doubly holographic model ». Journal of High Energy Physics 2021, n^o 5 (mai 2021). http://dx.doi.org/10.1007/jhep05(2021)135.

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Abstract We study the entanglement islands and subsystem volume complexity corresponding to the left/ right entanglement of a conformal defect in d-dimensions in Randall-Sundrum (RS) braneworld model with subcritical tension brane. The left and right modes of the defect mimic the eternal black hole and radiation system respectively. Hence the entanglement entropy between the two follows an eternal black hole Page curve which is unitarity compatible. We compute the volumes corresponding to the left and right branes with preferred Ryu-Takanayagi (RT) surfaces at different times, which provide a probe of the subregion complexity of the black hole and the radiation states respectively. An interesting jump in volume is found at Page time, where the entanglement curve is saturated due to the inclusion of the island surfaces. We explain various possibilities of this phase transition in complexity at Page time and argue how these results match with a covariant proposal qualitatively.

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Ray, Saibal, Shounak Ghosh et Rikpratik Sengupta. « Gravastar under the framework of braneworld gravity II : Effect of the Kuchowicz metric function ». Modern Physics Letters A, 22 décembre 2022. http://dx.doi.org/10.1142/s0217732322501954.

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In recent years, a class of compact objects called gravastars have drawn immense interest as regular solutions to end state stellar collapse. Since the energy density involved in collapse process is expected to be high, it is a natural choice to study such compact objects in context of modified gravity theories which reduce to General Relativity (GR) in the low energy regime. We have already framed a model of gravastar in such a modified gravity framework involving extra dimensional Randall–Sundrum (RS) single brane gravity [R. Sengupta, S. Ghosh, S. Ray, B. Mishra and S. K. Tripathy, Phys. Rev. D 102, 024037 (2020)]. As a sequel in this paper, we substantially improve our previous model by choosing the Kuchowicz function as one of the metric potentials, which leads to many new interesting results and physical features from our analysis as discussed in this paper. Also, we provide essential additional stability checks on our gravastar model to investigate the possibility of any instability creeping in due to the higher-dimensional framework. Our present improved gravastar model is found to clear all the stability checks successfully. Very interestingly, the static spherically symmetric matter distributions are found to accommodate both classes of solutions obeying and violating the modified energy conditions on the RS brane as we find in this work. We can conclude from our analysis that the Kuchowicz metric potential is very effective for describing regular solutions to compact objects at substantially high energies on the three-brane.

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Lagouri, Theodota. « Search for heavy resonances decaying into a pair of Z bosons using 139 fb−1 of p–p collisions at s=13 TeV with the ATLAS detector ». International Journal of Modern Physics A 37, n^o 07 (20 janvier 2022). http://dx.doi.org/10.1142/s0217751x21410074.

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This paper presents the search for heavy resonances decaying into a pair of [Formula: see text] bosons leading to the [Formula: see text] and [Formula: see text] final states, where [Formula: see text] stands for either an electron or a muon. The search uses proton–proton collision data at a center-of-mass energy of 13 TeV collected with the ATLAS detector from 2015 to 2018 corresponding to an integrated luminosity of 139 [Formula: see text], which is the full data statistics collected during the Run 2 of the Large Hadron Collider (LHC). The mass range for the hypothetical resonances considered spans from 200 GeV to 2000 GeV. In the absence of an observed significant excess, the results are interpreted as upper limits on the production cross-section of a spin-0 or spin-2 resonance. The upper limits for the spin-0 resonance are interpreted to exclusion contours in the context of Type-I and Type-II two-Higgs-doublet models (2HDM), while those for the spin-2 resonance are used to constrain the Randall–Sundrum (RS) model with an extra dimension giving rise to spin-2 graviton excitations.

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Folgado, Miguel G., Andrea Donini et Nuria Rius. « Spin-dependence of gravity-mediated dark matter in warped extra-dimensions ». European Physical Journal C 81, n^o 3 (mars 2021). http://dx.doi.org/10.1140/epjc/s10052-021-08989-x.

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AbstractWe study the possibility that Dark Matter (DM) particles of spin 0, 1/2 or 1 may interact gravitationally with Standard Model (SM) particles within the framework of a warped Randall–Sundrum (RS) model. Both the Dark Matter and the Standard Model particles are assumed to be confined to the infra-red (IR) brane and only interchange Kaluza–Klein excitations of the graviton and the radion (adopting the Goldberger–Wise mechanism to stabilize the size of the extra-dimension). We analyze the different DM annihilation channels and find that the presently observed Dark Matter relic abundance, $$\Omega _{\mathrm{DM}}$$ Ω DM , can be obtained within the freeze-out mechanism for DM particles of all considered spins. This extends our first work concerning scalar DM in RS scenarios (Folgado et al., in JHEP 01:161. 10.1007/JHEP01(2020)161, 2020) and put it on equal footing with our second work in which we studied DM particles of spin 0, 1/2 and 1 in the framework of the Clockwork/Linear Dilaton (CW/LD) model (Folgado et al., in JHEP 20:036. 10.1007/JHEP04(2020)036, 2020). We study the region of the model parameter space for which $$\Omega _{\mathrm{DM}}$$ Ω DM is achieved and compare it with the different experimental and theoretical bounds. We find that, for DM particles mass $$m_{\mathrm{DM}} \in [1,15]$$ m DM ∈ [ 1 , 15 ] TeV, most of the parameter space is excluded by the current constraints or will be excluded by the LHC Run III or by the LHC upgrade, the HL-LHC. The observed DM relic abundance can still be achieved for DM masses $$m_{\mathrm{DM}} \in [4,15]$$ m DM ∈ [ 4 , 15 ] TeV and $$m_{G_1} < 10$$ m G 1 < 10 TeV for scalar and vector boson Dark Matter. On the other hand, for spin 1/2 fermion Dark Matter, only a tiny region with $$m_{\mathrm{DM }} \in [4, 15]$$ m DM ∈ [ 4 , 15 ] TeV, $$m_{G_1} \in [5,10]$$ m G 1 ∈ [ 5 , 10 ] TeV and $$\Lambda > m_{G_1}$$ Λ > m G 1 is compatible with theoretical and experimental bounds. We have also studied the impact of the radion in the phenomenology, finding that it does not modify significantly the allowed region for DM particles of any spin (differently from the CW/LD case, where its impact was quite significant in the case of scalar DM). We, eventually, briefly compare results in RS with those obtained in the CW/LD model.

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Agrawal, Prateek, et Michael Nee. « Avoided deconfinement in Randall-Sundrum models ». Journal of High Energy Physics 2021, n^o 10 (octobre 2021). http://dx.doi.org/10.1007/jhep10(2021)105.

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Abstract We study first order phase transitions in Randall-Sundrum models in the early universe dual to confinement in large-N gauge theories. The transition rate to the confined phase is suppressed by a factor exp(−N2), and may not complete for N » 1, instead leading to an eternally inflating phase. To avoid this fate, the resulting constraint on N makes the RS effective field theory only marginally under control. We present a mechanism where the IR brane remains stabilized at very high temperature, so that the theory stays in the confined phase at all times after inflation and reheating. We call this mechanism avoided deconfinement. The mechanism involves adding new scalar fields on the IR brane which provide a stablilizing contribution to the radion potential at finite temperature, in a spirit similar to Weinberg’s symmetry non-restoration mechanism. Avoided deconfinement allows for a viable cosmology for theories with parametrically large N. Early universe cosmological phenomena such as WIMP freeze-out, axion abundance, baryogenesis, phase transitions, and gravitational wave signatures are qualitatively modified.

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Agrawal, Prateek, et Michael Nee. « Avoided deconfinement in Randall-Sundrum models ». Journal of High Energy Physics 2021, n^o 10 (octobre 2021). http://dx.doi.org/10.1007/jhep10(2021)105.

Texte intégral

Résumé :

Abstract We study first order phase transitions in Randall-Sundrum models in the early universe dual to confinement in large-N gauge theories. The transition rate to the confined phase is suppressed by a factor exp(−N2), and may not complete for N » 1, instead leading to an eternally inflating phase. To avoid this fate, the resulting constraint on N makes the RS effective field theory only marginally under control. We present a mechanism where the IR brane remains stabilized at very high temperature, so that the theory stays in the confined phase at all times after inflation and reheating. We call this mechanism avoided deconfinement. The mechanism involves adding new scalar fields on the IR brane which provide a stablilizing contribution to the radion potential at finite temperature, in a spirit similar to Weinberg’s symmetry non-restoration mechanism. Avoided deconfinement allows for a viable cosmology for theories with parametrically large N. Early universe cosmological phenomena such as WIMP freeze-out, axion abundance, baryogenesis, phase transitions, and gravitational wave signatures are qualitatively modified.

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