Search

We consider a class of $\text{SO}(10)$ models with flavor symmetries in the Yukawa sector and investigate their viability by performing numerical fits to the fermion masses and mixing parameters. The fitting procedure involves a top-down approach in which we solve the renormalization group equations from the scale of grand unification down to the electroweak scale. This allows the intermediate scale right-handed neutrinos and scalar triplet, involved in the type I and II seesaw mechanisms, to be integrated out at their corresponding mass scales, leading to a correct renormalization group running. The result is that, of the 14 models considered, only two are able to fit the known data well. Both these two models correspond to $\mathbb{Z}_2$ symmetries. In addition to being able to fit the fermion masses and mixing parameters, they provide predictions for the sum of light neutrino masses and the effective neutrinoless double beta decay mass parameter, which are both within current observational bounds., Comment: 19 pages, 4 tables. Final version published in JHEP

We discuss gauge mediated supersymmetry breaking models which explain the observed muon anomalous magnetic moment and the Higgs boson mass simultaneously. The successful explanation requires the messenger sector which violates the relation motivated by the grand unification theory (GUT). The naive violation of the GUT relation, however, ends up with the CP problem. We propose a model in which the phases of the gaugino masses are aligned despite the violation of the GUT relation. We also consider a model which generates the $\mu$-term and the additional Higgs soft masses squared without causing CP violation. As a result, we find a successful model which explains the muon anomalous magnetic moment and the Higgs boson mass. The model is also free from the CP, flavor-changing neutral current and the lepton flavor violation problems caused by the subdominant gravity mediation effects., Comment: 33 pages, 7 figures, Mass spectrum calculator: https://member.ipmu.jp/satoshi.shirai/sweetspot/sweetspotSUSY.php

We propose a model of fermion masses and mixings based on $SU(5)$ grand unified theory (GUT) and a $D_{4}$ flavor symmetry. This is a highly predictive 4D $SU(5)$ GUT with a flavor symmetry that does not contain a triplet irreducible representation. The Yukawa matrices of quarks and charged leptons are obtained after integrating out heavy messenger fields from renormalizable superpotentials while neutrino masses originate from the type I seesaw mechanism. The group theoretical factors from 24- and 45-dimensional Higgs fields lead to ratios between the Yukawa couplings in agreement with data, while the dangerous proton decay operators are highly suppressed. By performing a numerical fit, we find that the model captures accurately the mixing angles, the Yukawa couplings and the $CP$ phase of the quark sector at the GUT scale. The neutrino masses are generated at the renormalizable level with the prediction of trimaximal mixing while an additional effective operator is required to account for the baryon asymmetry of the universe (BAU). The model is remarkably predictive because only the normal neutrino mass ordering and the lower octant of the atmospheric angle are allowed while the $CP$ conserving values of the Dirac neutrino phase $\delta_{CP}$ are excluded. Moreover, the predicted values of the effective Majorana mass $m_{\beta \beta}$ can be tested at future neutrinoless double beta decay experiments. An analytical and a numerical study of the BAU via the leptogenesis mechanism is performed. We focused on the regions of parameter space where leptogenesis from the lightest right-handed neutrino is successfully realized. Strong correlations between the parameters of the neutrino sector and the observed BAU are obtained., Comment: 39 pages, 28 figures, matches published version

The vanishing of the Higgs quartic coupling of the Standard Model at high energies may be explained by spontaneous breaking of Higgs Parity. Taking Higgs Parity to originate from the Left-Right symmetry of the $SO(10)$ gauge group, leads to a new scheme for precision gauge coupling unification that is consistent with proton decay. We compute the relevant running of couplings and threshold corrections to allow a precise correlation among Standard Model parameters. The scheme has a built-in solution for obtaining a realistic value for $m_b/m_\tau$, which further improves the precision from gauge coupling unification, allowing the QCD coupling constant to be predicted to the level of 1 % or, alternatively, the top quark mass to 0.2 %. Future measurements of these parameters may significantly constrain the detailed structure of the theory. We also study an $SO(10)$ embedding of quark and lepton masses, showing how large neutrino mixing is compatible with small quark mixing, and predict a normal neutrino mass hierarchy. The strong CP problem may be explained by combining Higgs Parity with space-time parity., Comment: 39 pages, 9 figures

We employ a variety of symmetry breaking patterns in $SO(10)$ and $E_6$ Grand Unified Theories to demonstrate the appearance of topological defects including magnetic monopoles, strings, and necklaces. We show that independent of the symmetry breaking pattern, a topologically stable superheavy monopole carrying a single unit of Dirac charge as well as color magnetic charge is always present. Lighter intermediate mass topologically stable monopoles carrying two or three quanta of Dirac charge can appear in $SO(10)$ and $E_6$ models respectively. These lighter monopoles as well as topologically stable intermediate scale strings can survive an inflationary epoch. We also show the appearance of a novel necklace configuration in $SO(10)$ broken to the Standard Model via $SU(4)_c\times SU(2)_L\times SU(2)_R$. It consists of $SU(4)_c$ and $SU(2)_R$ monopoles connected by flux tubes. Necklaces consisting of monopoles and antimonopoles joined together by flux tubes are also identified. Even in the absence of topologically stable strings, a monopole-string system can temporarily appear. This system decays by emitting gravity waves and we provide an example in which the spectrum of these waves is strongly peaked around $10^{-4}~{\rm Hz}$ with $\Omega_{\rm gw}h^2\simeq 10^{-12}$. This spectrum should be within the detection capability of LISA., Comment: 21 pages including 3 figures, major revision, version to be published in JHEP

We study the textures of SM fermion mass matrices and their mixings in a supersymmetric adjoint SU(5) Grand Unified Theory with modular $S_4$ being the horizontal symmetry. The Yukawa entries of both quarks and leptons are expressed by modular forms with lower weights. Neutrino sector has an adjoint SU(5) representation 24 as matter superfield, which is a triplet of $S_4$. The effective light neutrino masses is generated through Type-III and Type-I seesaw mechanism. The only common complex parameter in both charged fermion and neutrino sectors is modulus $\tau$. Down-type quarks and charged leptons have the same joint effective operators with adjoint scalar in them, and their mass discrepancy in the same generation depends on Clebsch-Gordan factor. Especially for the first two generations the respective Clebsch-Gordan factors made the double Yukawa ratio $y_dy_{\mu}/y_ey_s=12$, in excellent agreement with the experimental result. We reproduce proper CKM mixing parameters and all nine Yukawa eigenvalues of quarks and charged leptons. Neutrino masses and MNS parameters are also produced properly with normal ordering is preferred., Comment: 24 pages,3 figures,Matches JHEP version

An axion-like particle (ALP) with mass mϕ ∼ 10−15 eV oscillates with frequency ∼1 Hz. This mass scale lies in an open window of astrophysical constraints, and appears naturally as a consequence of grand unification (GUT) in string/M-theory. However, with a GUT-scale decay constant such an ALP overcloses the Universe, and cannot solve the strong CP problem. In this paper, we present a two axion model in which the 1 Hz ALP constitutes the entirety of the dark matter (DM) while the QCD axion solves the strong CP problem but contributes negligibly to the DM relic density. The mechanism to achieve the correct relic densities relies on low-scale inflation (mϕ ≲ Hinf ≲ 1 MeV), and we present explicit realisations of such a model. The scale in the axion potential leading to the 1 Hz axion generates a value for the strong CP phase which oscillates around $$ {\overline{\theta}}_{\mathrm{QCD}}\sim {10}^{-12} $$ θ ¯ QCD ∼ 10 − 12 , within reach of the proton storage ring electric dipole moment experiment. The 1 Hz axion is also in reach of near future laboratory and astrophysical searches.

In this paper, a model inspired by Grand Unification principles featuring three generations of vector-like fermions, new Higgs doublets and a rich neutrino sector at the low scale is presented. Using the state-of-the-art Deep Learning techniques we perform the first phenomenological analysis of this model focusing on the study of new charged vector-like leptons (VLLs) and their possible signatures at CERN's Large Hadron Collider (LHC). In our numerical analysis we consider signal events for vector-boson fusion and VLL pair production topologies, both involving a final state containing a pair of charged leptons of different flavor and two sterile neutrinos that provide a missing energy. We also consider the case of VLL single production where, in addition to a pair of sterile neutrinos, the final state contains only one charged lepton. All calculated observables are provided as data sets for Deep Learning analysis, where a neural network is constructed, based on results obtained via an evolutive algorithm, whose objective is to maximise either the accuracy metric or the Asimov significance for different masses of the VLL. Taking into account the effect of the three analysed topologies, we have found that the combined significance for the observation of new VLLs at the high-luminosity LHC can range from $5.7\sigma$, for a mass of $1.25~\mathrm{TeV}$, all the way up to $28\sigma$ if the VLL mass is $200~\mathrm{GeV}$. We have also shown that by the end of the LHC Run-III a $200~\mathrm{GeV}$ VLL can be excluded with a confidence of $8.8$ standard deviations. The results obtained show that our model can be probed well before the end of the LHC operations and, in particular, providing important phenomenological information to constrain the energy scale at which new gauge symmetries emergent from the considered Grand Unification picture can be manifest., Comment: 60 pages, 31 figures, 15 tables

We discuss proton decay in a recently proposed model of supersymmetric hybrid inflation based on the gauge symmetry SU(4)c× SU(2)L× SU(2)R. A U(1) R symmetry plays an essential role in realizing inflation as well as in eliminating some undesirable baryon number violating operators. Proton decay is primarily mediated by a variety of color triplets from chiral superfields, and it lies in the observable range for a range of intermediate scale masses for the triplets. The decay modes include p → e+(μ+) + π0, $$ p\to \overline{\nu}+{\pi}^{+} $$ p → ν ¯ + π + , p → K0 + e+(μ+), and $$ p\to {K}^{+}+\overline{\nu} $$ p → K + + ν ¯ , with a lifetime estimate of order 1034–1036 yrs and accessible at Hyper-Kamiokande and future upgrades. The unification at the Grand Unified Theory (GUT) scale MGUT (∼ 1016 GeV) of the Minimal Supersymmetric Standard Model (MSSM) gauge couplings is briefly discussed.

We explore possible signatures for charged lepton flavour violation (LFV), sparticle discovery at the LHC and dark matter (DM) searches in grand unified theories (GUTs) based on SU(5), flipped SU(5) (FSU(5)) and SU(4)$_c \times $SU(2)$_L \times $SU(2)$_R$ (4-2-2). We assume that soft supersymmetry-breaking terms preserve the group symmetry at some high input scale, and focus on the non-universal effects on different matter representations generated by gauge interactions at lower scales, as well as the charged LFV induced in Type-1 see-saw models of neutrino masses. We identify the different mechanisms that control the relic DM density in the various GUT models, and contrast their LFV and LHC signatures. The SU(5) and 4-2-2 models offer good detection prospects both at the LHC and in LFV searches, though with different LSP compositions, and the SU(5) and FSU(5) models offer LFV within the current reach. The 4-2-2 model allows chargino and gluino coannihilations with neutralinos, and the former offer good detection prospects for both the LHC and LFV, while gluino coannihilations lead to lower LFV rates. Our results indicate that LFV is a powerful tool that complements LHC and DM searches, providing significant insights into the sparticle spectra and neutrino mass parameters in different models., Comment: 27 pages, 8 figures

We introduce dark matter (DM) evolution process in the Sun under a two-component DM (2DM) scenario. Both DM species $\chi$ and $\xi$ with masses heavier than 1 GeV are considered. In this picture, both species could be captured by the Sun through DM-nucleus scattering and DM self-scatterings, e.g. $\chi\chi$ and $\xi\xi$ collisions. In addition, the heterogeneous self-scattering due to $\chi$ and $\xi$ collision is essentially possible in any 2DM models. This new introduced scattering naturally weaves the evolution processes of the two DM species that was assumed to evolve independently. Moreover, the heterogeneous self-scattering enhances the number of DM being captured in the Sun mutually. This effect significantly exists in a broad range of DM mass spectrum. We have studied this phenomena and its implication for the solar-captured DM annihilation rate. It would be crucial to the DM indirect detection when the two masses are close. General formalism of the 2DM evolution in the Sun as well as its kinematics are studied., Comment: 25 pages and 7 figures, minor revision, results unchanged, references added

We show that a universal texture zero in the (1,1) position of all fermionic mass matrices, including heavy right-handed Majorana neutrinos driving a type-I see-saw mechanism, can lead to a viable spectrum of mass, mixing and CP violation for both quarks and leptons, including (but not limited to) three important postdictions: the Cabibbo angle, the charged lepton masses, and the leptonic `reactor' angle. We model this texture zero with a non-Abelian discrete family symmetry that can easily be embedded in a grand unified framework, and discuss the details of the phenomenology after electroweak and family symmetry breaking. We provide an explicit numerical fit to the available data and obtain excellent agreement with the 18 observables in the charged fermion and neutrino sectors with just 9 free parameters. We further show that the vacua of our new scalar familon fields are readily aligned along desired directions in family space, and also demonstrate discrete gauge anomaly freedom at the relevant scale of our effective theory., 17 pages, 2 figures. Version accepted for publication in JHEP

Recent encouraging experimental results on neutrino mixing parameters prompt further investigation on $SO(10)$-inspired leptogenesis and on the associated strong thermal solution that has correctly predicted a non-vanishing reactor mixing angle, it further predicts $\sin\delta \lesssim 0$, now supported by recent results at $\sim 95\%$ C.L., normally ordered neutrino masses and atmospheric mixing angle in the first octant, best fit results in latest global analyses. Extending a recent analytical procedure, we account for the mismatch between the Yukawa basis and the weak basis, that in $SO(10)$-inspired models is described by a CKM-like unitary transformation $V_L$, obtaining a full analytical solution that provides useful insight and reproduces accurately all numerical results, paving the way for future inclusion of different sources of theoretical uncertainties and for a statistical analysis of the constraints. We show how muon-dominated solutions appear for large values of the lightest neutrino mass in the range $(0.01$--$1)\,{\rm eV}$ but also how they necessarily require a mild fine tuning in the seesaw relation. For the dominant (and untuned) tauon-dominated solutions we show how, turning on $V_L \simeq V_{CKM}$, some of the constraints on the low energy neutrino parameters get significantly relaxed. In particular we show how the upper bound on the atmospheric neutrino mixing angle in the strong thermal solution gets relaxed from $\theta_{23} \lesssim 41^{\circ}$ to $\theta_{23} \lesssim 44^{\circ}$, an important effect in the light of the most recent NO$\nu$A, T2K and IceCube results., Comment: 34 pages, 4 figures; v2: matches JHEP version; v3: simple typo corrected: right-hand sides of Eqs. (47) and (48) were swapped in the paper (not in the code)

We investigate the possibility of viable leptogenesis in an appealing $\Delta(27)$ model with a universal texture zero in the (1,1) entry. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both $N_1$ and $N_2$ right-handed neutrino decays. The $N_1$-dominated scenario is successful and the most natural option for the model, with $M_1 \in [10^9, 10^{12}]$ GeV, and $M_1/M_2 \in [0.002, 0.1]$, which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the $N_2$-dominated scenario, with the asymmetry in the electron flavour protected from $N_1$ washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy $M_1/M_2 < 0.002 $, and $M_2$ relatively close to $M_3$, which is not a natural expectation of the $\Delta(27)$ model., Comment: v2: 20 pages, 2 figures. Version accepted in JHEP

Anomalies can be elegantly analyzed by means of the Dai-Freed theorem. In this framework it is natural to consider a refinement of traditional anomaly cancellation conditions, which sometimes leads to nontrivial extra constraints in the fermion spectrum. We analyze these more refined anomaly cancellation conditions in a variety of theories of physical interest, including the Standard Model and the $SU(5)$ and $Spin(10)$ GUTs, which we find to be anomaly free. Turning to discrete symmetries, we find that baryon triality has a $\mathbb{Z}_9$ anomaly that only cancels if the number of generations is a multiple of 3. Assuming the existence of certain anomaly-free $\mathbb{Z}_4$ symmetry we relate the fact that there are 16 fermions per generation of the Standard Model - including right-handed neutrinos - to anomalies under time-reversal of boundary states in four-dimensional topological superconductors. A similar relation exists for the MSSM, only this time involving the number of gauginos and Higgsinos, and it is non-trivially, and remarkably, satisfied for the $SU(3)\times SU(2) \times U(1)$ gauge group with two Higgs doublets. We relate the constraints we find to the well-known Iba\~nez-Ross ones, and discuss the dependence on UV data of the construction. Finally, we comment on the (non-)existence of K-theoretic $\theta$ angles in four dimensions., Comment: 83 pages, 22 figures, many arrows v2: Minor changes, improved discussion of discrete symmetry anomalies. v3: Expanded and corrected bordism table in Appendix

The observed low-energy values of the $SU(3)\times SU(2)\times U(1)$ gauge couplings, extrapolated via the minimal Standard Model Renormalization Group evolution, hint at the exciting possibility of a Grand Unified Theory (GUT) at $M_U \sim 10^{14}$ GeV --- a scale, however, too high to probe directly via collider searches. Fortunately, since the Hubble scale H can be as high as $5 \times 10^{13}$ GeV $\sim M_U$ during the inflationary era, such GUT scale states can be cosmologically produced at that time and leave direct on-shell signatures such as their masses and spins, via primordial non-Gaussianity (NG). We explore this possibility in one of its simplest realizations given by the extra-dimensional framework of orbifold GUTs, in which proton decay can be straightforwardly suppressed to be within the stringent bounds. Here, along with the massive GUT states there must also be H-mass spin-2 Kaluza-Klein (KK) gravitons, collectively giving rise to striking NG signatures. In our set-up we localize the inflaton on one of the boundaries of an extra dimension. The inflationary vacuum energy can readily lead to formation of a horizon in the bulk, where the KK modes then form a continuum above a mass gap of $\sim \mathcal{O}(H)$. We find that the optimal case for observable NG signals is when the extra dimension is stabilized close to the onset of this horizon, ensuring a discrete KK spectrum such that the lightest KK modes can be cosmologically produced without significant Boltzmann suppressions. Although we mostly focus on the case where there is no higher-dimensional cosmological constant, we also obtain considerable holographic insights from the $\text{AdS}_5/\text{CFT}_4$ correspondence when such a cosmological constant is included., v1: 30+10 pages, 6 figures; v2: discussion added at the end of subsection 4.3, reference added, conclusions unchanged, journal version

Here we correct some typesetting errors in affiliations.

We propose a composite grand unified theory to study the anomalies in the semileptonic $B$ decays. We show a simple group containing the custodial and Standard Model gauge symmetries, that can deliver a set of composite pseudo Nambu-Goldstone bosons: the Higgs, a colorless SU(2)$_L$-fourplet and three leptoquarks: a triplet and two doublets. We give a description in terms of an effective theory of resonances. By assuming anarchic partial compositeness of the Standard Model fermions, we find representations for the composite fermions that allow to obtain the Higgs Yukawa couplings, as well as leptoquark interactions explaining the deviations in $R^{\mu e}_{K^{(*)}}$. We calculate the one-loop potential, we show that it can trigger electroweak symmetry breaking and we find a region of the parameter space that can reproduce the Standard Model spectrum. The model predicts leptoquark masses of order $0.4-1.3$ TeV, corrections to some electroweak observables, with $Zb_L\bar b_L$ saturating the current bounds, and a very reach phenomenology at LHC. We also study the possibility of explaining $R^{\tau\ell}_{D^{(*)}}$., Comment: 36 pages, 4 figures, v2: typos corrected, references added

We discuss the 750 GeV diphoton excess at the LHC@13TeV in the framework of leptophobic U(1)$^\prime$ model inspired by $E_6$ grand unified theory (GUT). In this model, the Standard Model (SM) chiral fermions carry charges under extra U(1)$^\prime$ gauge symmetry which is spontaneously broken by a U(1)$^\prime$-charged singlet scalar ($\Phi$). In addition, extra quarks and leptons are introduced to achieve the anomaly-free conditions, which is a natural consequence of the assumed $E_6$ GUT. These new fermions are vectorlike under the SM gauge group but chiral under new U(1)$^\prime$, and their masses come entirely from the nonzero vacuum expectation value of $\Phi$ through the Yukawa interactions. Then, the CP-even scalar $h_\Phi$ from $\Phi$ can be produced at the LHC by the gluon fusion and decay to the diphoton via the one-loop diagram involving the extra quarks and leptons, and can be identified as the origin of diphoton excess at 750 GeV. In this model, $h_\Phi$ can decay into a pair of dark matter particles as well as a pair of scalar bosons, thereby a few tens of the decay width may be possible., Comment: 21 pages, 4 figures. Published version

We systematically develop the formalism necessary for ensuring that boundary conditions of flavon fields in extra dimensions are consistent with heterotic string theory. Having developed a set of consistency conditions on the boundary conditions, we explore a series of examples of orbifolds in various dimensions to see which ones can satisfy them. In addition we impose the further phenomenological requirements of having non-trivial flavon vacuum alignments and also of having quarks and leptons located appropriately in extra dimensions. The minimal successful case seems to be a 10d theory with a SU(3)fl gauged flavour symmetry, where the six-dimensional torus is compactified on a 𝕋6 /∆(54) orbifold. We construct a realistic SU(5) grand unified theory along these lines, leading to tribimaximal-reactor lepton mixing, which we show to be consistent with current neutrino data.

We explore the sparticle mass spectra including LSP dark matter within the framework of supersymmetric SU(4)(c) x SU(2)(L) x SU(2)(R) (422) models, taking into account the constraints from extensive LHC and cold dark matter searches. The soft supersymmetry-breaking parameters at M-GUT can be non-universal, but consistent with the 422 symmetry. We identify a variety of coannihilation scenarios compatible with LSP dark matter, and study the implications for future supersymmetry searches and the ongoing muon g-2 experiment., M.E.G. research was supported by the Spanish MINECO, under grants FPA2014-53631- C-2-P and FPA2017-86380-P. R. RdA is supported by the Ramón y Cajal program of the Spanish MICINN, the Elusives European ITN project (H2020-MSCA-ITN-2015//674896- ELUSIVES), the \SOM Sabor y origen de la Materia" (PROMETEOII/2014/050) and Centro de excelencia Severo Ochoa Program under grant SEV-2014-0398. Q.S. acknowledges support by the DOE grant No. DE-SC0013880. We also thank F. Márquez Saldaña for useful discussions.

We estimate the current theoretical uncertainty in supersymmetric dark matter predictions by comparing several state-of-the-art calculations within the minimal supersymmetric standard model (MSSM). We consider standard neutralino dark matter scenarios -- coannihilation, well-tempering, pseudoscalar resonance -- and benchmark models both in the pMSSM framework and in frameworks with Grand Unified Theory (GUT)-scale unification of supersymmetric mass parameters. The pipelines we consider are constructed from the publicly available software packages SOFTSUSY, SPheno, FeynHiggs, SusyHD, micrOMEGAs, and DarkSUSY. We find that the theoretical uncertainty in the relic density as calculated by different pipelines, in general, far exceeds the statistical errors reported by the Planck collaboration. In GUT models, in particular, the relative discrepancies in the results reported by different pipelines can be as much as a few orders of magnitude. We find that these discrepancies are especially pronounced for for cases where the dark matter physics relies critically on calculations related to electroweak symmetry breaking, which we investigate in detail, and for coannihilation models, where there is heightened sensitivity to the sparticle spectrum. The dark matter annihilation cross section today and the scattering cross section with nuclei also suffer appreciable theoretical uncertainties, which, as experiments reach the relevant sensitivities, could lead to uncertainty in conclusions regarding the viability or exclusion of particular models., Comment: v2: minor changes, references added

Searching for heavy vector bosons $Z^\prime$, predicted in models inspired by Grand Unification Theories, is among the challenging objectives of the LHC. The ATLAS and CMS collaborations have looked for $Z^\prime$ bosons assuming that they can decay only into Standard Model channels, and have set exclusion limits by investigating dilepton, dijet and to a smaller extent top-antitop final states. In this work we explore possible loopholes in these $Z^\prime$ searches by studying supersymmetric as well as leptophobic scenarios. We demonstrate the existence of realizations in which the $Z^\prime$ boson automatically evades the typical bounds derived from the analyses of the Drell-Yan invariant-mass spectrum. Dileptonic final states can in contrast only originate from supersymmetric $Z^\prime$ decays and are thus accompanied by additional effects. This feature is analyzed in the context of judiciously chosen benchmark configurations, for which visible signals could be expected in future LHC data with a $4\sigma-7\sigma$ significance. Our results should hence motivate an extension of the current $Z^\prime$ search program to account for supersymmetric and leptophobic models., Comment: 32 pages, 15 figures. After JHEP revision. Published on 15 February 2018

We propose a natural S 4 × SO(10) supersymmetric grand unified theory of flavour with an auxiliary $$ {\mathbb{Z}}_4^2\times {\mathbb{Z}}_4^R $$ symmetry, based on small Higgs representations (nothing larger than an adjoint) and hence a type-I seesaw mechanism. The Yukawa structure of all fermions is determined by the hierarchical vacuum expectation values of three S 4 triplet flavons, with CSD3 vacuum alignments, where up-type quarks and neutrinos couple to one Higgs 10, and the down-type quarks and charged leptons couple to a second Higgs 10. The Yukawa matrices are obtained from sums of low-rank matrices, where each matrix in the sum naturally accounts for the mass of a particular family, as in sequential dominance in the neutrino sector, which predicts a normal neutrino mass hierarchy. The model accurately fits all available quark and lepton data, with predictions for the leptonic CP phase in 95% credible intervals given by 281° < δ l < 308° and 225° < δ l < 253°. The model reduces to the MSSM, with the two Higgs doublets emerging from the two Higgs 10s without mixing, and we demonstrate how a μ term of $$ \mathcal{O}\left(\mathrm{T}\mathrm{e}\mathrm{V}\right) $$ can be realised, as well as doublet-triplet splitting, with Planck scale operators controlled by symmetry, leading to acceptable proton decay.

The methodology of the heterotic mini-landscape attempts to zero in on phenomenologically viable corners of the string landscape where the effective low energy theory is the Minimal Supersymmetric Standard Model with localized grand unification. The gaugino mass pattern is that of mirage-mediation. The magnitudes of various SM Yukawa couplings point to a picture where scalar soft SUSY breaking terms are related to the geography of fields in the compactified dimensions. Higgs fields and third generation scalars extend to the bulk and occur in split multiplets with TeV scale soft masses. First and second generation scalars, localized at orbifold fixed points or tori with enhanced symmetry, occur in complete GUT multiplets and have much larger masses. This picture can be matched onto the parameter space of generalized mirage mediation. Naturalness considerations, the requirement of the observed electroweak symmetry breaking pattern, and LHC bounds on m(gluino) together limit the gravitino mass to the m_{3/2}~ 5-60 TeV range. The mirage unification scale is bounded from below with the limit depending on the ratio of squark to gravitino masses. We show that while natural SUSY in this realization may escape detection even at the high luminosity LHC, the high energy LHC with \sqrt{s}=33 TeV could unequivocally confirm or exclude this scenario. It should be possible to detect the expected light higgsinos at the ILC if these are kinematically accessible, and possibly also discriminate the expected compression of gaugino masses in the natural mini-landscape picture from the mass pattern expected in models with gaugino mass unification. The thermal WIMP signal should be accessible via direct detection searches at the multi-ton noble liquid detectors such as Xenon-nT or LZ., 33 pages with 32 .png figures

SU(5) $\otimes$ SU(5) provides a minimal grand unification scheme for fermions and gauge forces if there are vector-like quarks and leptons in nature. We explore the gauge coupling unification in a non-supersymmetric model of this type, and study its implications for proton decay. The properties of vector-like quarks and intermediate scales that emerge from coupling unification play a central role in suppressing proton decay. We find that in this model, the familiar decay mode $p \to e^+ \pi^0$ may have a partial lifetime within the reach of currently planned experiments.

We propose a Grand Unified Theory of Flavour, based on SO(10) together with a non-Abelian discrete group S4, under which the unified three quark and lepton 16-plets are unified into a single triplet 3′. The model involves a further discrete group ℤ 4 R × ℤ 4 3 which controls the Higgs and flavon symmetry breaking sectors. The CSD2 flavon vacuum alignment is discussed, along with the GUT breaking potential and the doublet-triplet splitting, and proton decay is shown to be under control. The Yukawa matrices are derived in detail, from renormalisable diagrams, and neutrino masses emerge from the type I seesaw mechanism. A full numerical fit is performed with 15 input parameters generating 19 presently constrained observables, taking into account supersymmetry threshold corrections. The model predicts a normal neutrino mass ordering with a CP oscillation phase of 260°, an atmospheric angle in the first octant and neutrinoless double beta decay with m ββ = 11 meV. We discuss N2 leptogenesis, which fixes the second right-handed neutrino mass to be M2 ≃ 2 × 1011 GeV, in the natural range predicted by the model.

A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted dark matter annihilation rate, new relativistic degrees of freedom, warm dark matter, and observable distortions to the spectrum of the cosmic microwave background., Comment: 26 pages plus appendix, 11 figures, minor changes to v1

Phenomenologically appealing supersymmetric grand unified theories have large gauge representations and thus are not asymptotically free. Their ultraviolet validity is limited by the appearance of a Landau pole well before the Planck scale. One could hope that these theories save themselves, before the inclusion of gravity, by generating an interacting ultraviolet fixed point, similar to the one recently discovered in non-supersymmetric gauge-Yukawa theories. Employing a-maximization, a-theorem, unitarity bounds, as well as positivity of other central charges we nonperturbatively rule out this possibility for a broad class of prime candidates of phenomenologically relevant supersymmetric grand unified theories. We also uncover candidates passing these tests, which have either exotic matter or contain one field decoupled from the superpotential. The latter class of theories contains a model with the minimal matter content required by phenomenology., 1 figure, section on the doublet-triplet problem added, new references, accepted in JHEP

Precision gauge coupling unification is one of the primary quantitative successes of low energy or split supersymmetry. Preserving this success puts severe restrictions on possible matter and gauge sectors that might appear at collider-accessible energies. In this work we enumerate new gauge sectors which are compatible with unification, consisting of horizontal gauge groups acting on vector-like matter charged under the Standard Model. Interestingly, almost all of these theories are in the supersymmetric conformal window at high energies and confine quickly after the superpartners are decoupled. For a range of scalar masses compatible with both moderately tuned and minimally split supersymmetry, the confining dynamics happen at the multi-TeV scale, leading to a spectrum of multiple spin-0 and spin-1 resonances accessible to the LHC, with unusual quantum numbers and striking decay patterns., 27 pages, 6 figures

We consider a conformal complex singlet extension of the Standard Model with a Higgs portal interaction. The global $U(1)$ symmetry of the complex singlet can be either broken or unbroken and we study each scenario. In the unbroken case, the global $U(1)$ symmetry protects the complex singlet from decaying, leading to an ideal cold dark matter candidate with approximately 100 GeV mass along with a significant proportion of thermal relic dark matter abundance. In the broken case, we have developed a renormalization-scale optimization technique to significantly narrow the parameter space and in some situations, provide unique predictions for all the model's couplings and masses. We have found there exists a second Higgs boson with a mass of approximately $550\,\rm{GeV}$ that mixes with the known $125\,\rm{GeV}$ Higgs with a large mixing angle $\sin\theta\approx 0.47$ consistent with current experimental limits. The imaginary part of the complex singlet in the broken case could provide axion dark matter for a wide range of models. Upon including interactions of the complex scalar with an additional vector-like fermion, we explore the possibility of a diphoton excess in both the unbroken and the broken cases. In the unbroken case, the model can provide a natural explanation for diphoton excess if extra terms are introduced providing extra contributions to the singlet mass. In the broken case, we find a set of coupling solutions that yield a second Higgs boson of mass $720\,\rm{GeV}$ and an $830\,\rm{GeV}$ extra vector-like fermion $F$, which is able to address the $750\,\rm{GeV}$ LHC diphoton excess. We also provide criteria to determine the symmetry breaking pattern in both the Higgs and hidden sectors., Comment: 12 pages and 1 figure. Published in JHEP

In previous work, we presented a statistical scan over the soft supersymmetry breaking parameters of the minimal SUSY $B-L$ model. For specificity of calculation, unification of the gauge parameters was enforced by allowing the two ${\mathbb Z}_{3}\times {\mathbb Z}_{3}$ Wilson lines to have mass scales separated by approximately an order of magnitude. This introduced an additional "left-right" sector below the unification scale. In this paper, for three important reasons, we modify our previous analysis by demanding that the mass scales of the two Wilson lines be simultaneous and equal to an "average unification" mass $\left$. The present analysis is 1) more "natural" than the previous calculations, which were only valid in a very specific region of the Calabi-Yau moduli space, 2) the theory is conceptually simpler in that the left-right sector has been removed and 3) in the present analysis the lack of gauge unification is due to threshold effects--particularly heavy string thresholds, which we calculate statistically in detail. As in our previous work, the theory is renormalization group evolved from $\left$ to the electroweak scale--being subjected, sequentially, to the requirement of radiative $B-L$ and electroweak symmetry breaking, the present experimental lower bounds on the $B-L$ vector boson and sparticle masses, as well as the lightest neutral Higgs mass of $\sim$125 GeV. The subspace of soft supersymmetry breaking masses that satisfies all such constraints is presented and shown to be substantial., Comment: 45 pages, 19 figures. References added. Brief review of the B-L MSSM formalism in arXiv:1503.01473 included for clarity. Typographical errors corrected

We investigate the 750 GeV diphoton excess in terms of supersymmetric models which preserve grand unification in the ultraviolet. We show that minimal extensions of the MSSM by a singlet and a vector-like 5-plet or 10-plet of SU(5) can explain the observed signal while remaining perturbative up to the GUT scale. Different from previous analyses we rely on light sfermions in the loops which - compared to the analog non-supersymmetric models - enhance the diphoton cross section by up to a factor of seven. While the resonance decay width is narrow, mass splitting of the scalar and pseudoscalar components may result in a double resonance. We perform a likelihood analysis on the ATLAS and CMS data to show that the significance of the diphoton excess increases from 3.3 sigma (single narrow resonance) to 3.9 sigma for the double resonance. We also provide signal predictions in other diboson channels to be tested at LHC-13., 20 pages, 6 figures

We study a class of realizations of the Next-to-Minimal Supersymmetric Standard Model that is motivated by dark matter and Higgs data, and in which the lightest pseudoscalar Higgs boson mass is smaller than twice the bottom quark mass and greater than twice the tau lepton mass. In such scenarios, the lightest pseudoscalar Higgs boson can be copiously produced at the LHC from the decay of heavier superpartners and will dominantly further decay into a pair of tau leptons that is generally boosted. We make use of a boosted object tagging technique designed to tag such a ditau jet, and estimate the sensitivity of the LHC to the considered supersymmetric scenarios with 20 to 50~fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13~TeV., 17 pages, 7 figures. Version to be published in JHEP

The CMS experiment at the Large Hadron Collider has reported a 2.8$\sigma$ excess in the $(2e)(2jets)$ channel around 2.1 TeV. Interpretation of this data is reconsidered in terms of the production of a right-handed weak gauge boson, $W_R$, of the left-right symmetric model and in an $SO(10)$ grand unified theory abiding by the Extended Survival Hypothesis. The left-right symmetric model can be consistent with this excess if (a) the heavy right-handed neutrino has a mass near $W_R$, or (b) if $g_L \neq g_R$, or (c) the right-handed CKM matrix is nontrivial. Combinations of the above possibilities are also viable. A $W_R$ with a mass in the TeV region if embedded in $SO(10)$ is not compatible with $g_L = g_R$. Rather, it implies $0.64 \leq g_R/g_L \leq 0.78$. Further, a unique symmetry-breaking route -- the order being left-right discrete symmetry breaking first, followed by $SU(4)_C$ and finally $SU(2)_R$ -- to the standard model is picked out. The $L \leftrightarrow R$ discrete symmetry has to be broken at around $10^{16}$ GeV. The grand unification scale is pushed to $10^{18}$ GeV making the detection of proton decay in ongoing searches rather unlikely. The $SU(4)_C$ breaking scale can be at its allowed lower limit of $10^6$ GeV so that $n - \bar{n}$ oscillation or flavour changing processes such as $K_L \rightarrow \mu e$ and $B_{d,s} \rightarrow \mu e$ may be detectable. The Higgs scalar multiplets responsible for $SO(10)$ symmetry breaking at various stages are uniquely identified so long as one adheres to a minimalist principle. We also remark, {\em en passant}, about a partially unified Pati-Salam model., Comment: 21 pages, v2: Published version. Clarifications and references added

We consider a right-handed scalar neutrino as the inflaton which carries a gravitational coupling with a supersymmetric QCD sector responsible for breaking supersymmetry dynamically. The framework suggests an inflaton potential which is a deformed version of the quadratic chaotic inflation leading to a flatter potential. We find that this deformation results a sizable tensor to scalar ratio which falls within the allowed region by PLANCK 2015. At the same time supersymmetry breaking at the end of inflation can naturally be induced in this set-up. The symmetries required to construct the framework allows the neutrino masses and mixing to be of right order., 24 pages, 3 figures; version to appear in JHEP

The sweet spot supersymmetry (SUSY) solves the mu problem in the Minimal Supersymmetric Standard Model (MSSM) with gauge mediated SUSY breaking (GMSB) via the generalized Giudice-Masiero (GM) mechanism where only the mu-term and soft Higgs masses are generated at the unification scale of the Grand Unified Theory (GUT) due to the approximate PQ symmetry. Because all the other SUSY breaking soft terms are generated via the GMSB below the GUT scale, there exists SUSY electroweak (EW) fine-tuning problem to explain the 125 GeV Higgs boson mass due to small trilinear soft term. Thus, to explain the Higgs boson mass, we propose the GMSB with both the generalized GM mechanism and Higgs-messenger interactions. The renormalization group equations are runnings from the GUT scale down to EW scale. So the EW symmetry breaking can be realized easier. We can keep the gauge coupling unification and solution to the flavor problem in the GMSB, as well as solve the \mu/B_{\mu}-problem. Moreover, there are only five free parameters in our model. So we can determine the characteristic low energy spectra and explore its distinct phenomenology. The low-scale fine-tuning measure can be as low as 20 with the light stop mass below 1 TeV and gluino mass below 2 TeV. The gravitino dark matter can come from a thermal production with the correct relic density and be consistent with the thermal leptogenesis. Because gluino and stop can be relatively light in our model, how to search for such GMSB at the upcoming run II of the LHC experiment could be very interesting., Comment: 22 pages, 7 figures, Latex

We construct an extension of the Standard Model (SM) which is based on grand unification with Pati-Salam symmetry. The setup is supplemented with the idea of spontaneous flavour symmetry breaking which is mediated through flavon fields with renormalizable couplings to new heavy fermions. While we argue that the new gauge bosons in this approach can be sufficiently heavy to be irrelevant at low energies, the fermionic partners of the SM quarks, in particular those for the third generation, can be relatively light and provide new sources of flavour violation. The size of the effects is constrained by the observed values of the SM Yukawa matrices, but in a way that is different from the standard minimal-flavour violation approach. We determine characteristic deviations from the SM that could eventually be observed in future precision measurements., 26 pages, 5 figures

We propose a renormalisable model based on A 4 family symmetry with an SU(5) grand unified theory (GUT) which leads to the minimal supersymmetric standard model (MSSM) with a ℤ 9 × ℤ 6 symmetry provides the fermion mass hierarchy in both the quark and lepton sectors, while ℤ 4 R symmetry is broken to ℤ 2 R , identified as usual R-parity. Proton decay is highly sup-pressed by these symmetries. The strong CP problem is solved in a similar way to the Nelson-Barr mechanism. We discuss both the A 4 and SU(5) symmetry breaking sectors, including doublet-triplet splitting, Higgs mixing and the origin of the μ term. The model provides an excellent fit (better than one sigma) to all quark and lepton (including neu-trino) masses and mixing with spontaneous CP violation. With the A 4 vacuum alignments, (0, 1, 1) and (1, 3, 1), the model predicts the entire PMNS mixing matrix with no free pa-rameters, up to a relative phase, selected to be 2π/3 from a choice of the nine complex roots of unity, which is identified as the leptogenesis phase. The model predicts a normal neutrino mass hierarchy with leptonic angles θ 13 ι ≈ 8.7 ∘ , θ 12 ι ≈ 34 ∘ , θ 23 ι ≈ 46 ∘ and an oscillation phase δ ι ≈ − 87 ∘ .

We show explicitly that supersymmetric E 6 Grand Unified Theory with a Higgs sector consisting of $$ \left\{27 + \overline{27} + {351}^{\prime } + {\overline{351}}^{\prime } + 78\right\} $$ fields provides a realistic scenario for symmetry breaking and fermion mass generation. While gauge symmetry breaking can be achieved without the 78 field, its presence is critical for a successful doublet-triplet mass splitting. The Yukawa sector of the model consists of only two symmetric matrices describing all of quark, lepton and neutrino masses and mixings. The fermion mass matrices are computed at low energy and a fit to the second and third generation masses and mixings is performed. We find a good numerical fit to the low-energy data. Thus, this model, having 11 superpotential parameters, alongside the two symmetric Yukawa matrices, seems to be the best realistic candidate for a minimal renormalizable supersymmetric E 6 unified theory.

Motivated by future collider proposals that aim to measure the Higgs properties precisely, we study the partial decay widths of the lightest Higgs boson in the minimal supersymmetric standard model with an emphasis on the parameter region where all superparticles and heavy Higgs bosons are not accessible at the LHC. Taking account of phenomenological constraints such as the Higgs mass, flavor constraints, vacuum stability, and perturbativity of coupling constants up to the grand unification scale, we discuss how large the deviations of the partial decay widths from the standard model predictions can be. These constraints exclude large fraction of the parameter region where the Higgs widths show significant deviation from the standard model predictions. Nevertheless, even if superparticles and the heavy Higgses are out of the reach of 14TeV LHC, the deviation may be large enough to be observed at future $e^+e^-$ collider experiments., Comment: 24 pages, 8 figures, version accepted in JHEP

With the assistance of two extra groups, i.e., an extra hidden gauge group $SU(2)_D$ and a global $U(1)$ group, we propose a two component dark matter (DM) model. After the symmetry $SU(2)_D\times U(1)$ being broken, we obtain both the vector and scalar DM candidates. The two DM candidates communicate with the standard model (SM) via three Higgs as multi-Higgs portals. The three Higgs are mixing states of the SM Higgs, the Higgs of the hidden sector and real part of a supplement complex scalar singlet. We study relic density and direct detection of DM in three scenarios. The resonance behaviors and interplay between the two component DM candidates are represented through investigating of the relic density in the parameter spaces of the two DMs masses. The electroweak precision parameters constrains the two Higgs portals couplings ($\lambda_m$ and $\delta_2$). The relevant vacuum stability and naturalness problem in the parameter space of $\lambda_m$ and $\delta_2$ are studied as well. The model could alleviate these two problems in some parameter spaces under the constraints of electroweak precision observables and Higgs indirect search., Comment: 27 pages, 16 figures. Version accepted for publication in JHEP

We calculate the effective $$ Zb\overline{b} $$ coupling at one loop level, in the framework of non-minimal Universal Extra Dimensional (nmUED) model. Non-minimality in Universal Extra Dimensional (UED) framework is realized by adding kinetic and Yukawa terms with arbitrary coefficients to the action at boundary points of the extra space like dimension. A recent estimation of the Standard Model (SM) contribution to $$ Zb\overline{b} $$ coupling at two loop level, points to a 1.2σ discrepancy between the experimental data and the SM estimate. We compare our calculation with the difference between the SM prediction and the experimental estimation of the above coupling and constrain the parameter space of nmUED. We also review the limit on compactification radius of UED in view of the new theoretical estimation of SM contribution to $$ Zb\overline{b} $$ coupling. For suitable choice of coefficients of boundary-localized terms, 95% C.L. lower limit on R −1 comes out to be in the ballpark of 800 GeV in the framework of nmUED; while in UED, the lower limit on R −1 is 350 GeV which is a marginal improvement over an earlier estimate.

We analyze the running at one-loop of the gauge couplings in the spectral Pati-Salam model that was derived in the framework of noncommutative geometry. There are a few different scenario's for the scalar particle content which are determined by the precise form of the Dirac operator for the finite noncommutative space. We consider these different scenarios and establish for all of them unification of the Pati-Salam gauge couplings. The boundary conditions are set by the usual RG flow for the Standard Model couplings at an intermediate mass scale at which the Pati-Salam symmetry is broken., Comment: 8 pages

We study models of supersymmetric grand unification based on the SO(10) gauge group. We investigate scenarios of non-universal gaugino masses including models containing a mixture of two representations of hidden sector chiral superfields. We analyse the effect of excluding mu from the fine-tuning measure, and confront the results with low energy constraints, including the Higgs boson mass, dark matter relic density and supersymmetry bounds. We also determine high scale Yukawa coupling ratios and confront the results with theoretical predictions. Finally, we present two additional benchmarks that should be explored at the LHC and future colliders., Comment: Published version

We propose a simplified light higgsino-singlino scenario in the NMSSM, in which the masses of the chargino and the lightest neutralino determine the masses and couplings of all 3 lightest neutralinos. This scenario is complementary to the simplified wino-like chargino/neutralino scenario used conventionally for the interpretation of results from trilepton searches, and motivated by lower bounds on the gluino mass in the case of GUT relations between the wino and gluino masses. We present all masses and mixing angles necessary for the determination of production cross sections of the chargino and the 3 neutralinos in the form of Tables in the M_{neutralino_1} - M_{chargino_1} plane, assuming Higgs mass motivated values for tan(beta)=2 and lambda=0.6. We show that this scenario leads to considerable signal rates, and present constraints in this plane from recent searches for trileptons at the LHC., Comment: 16 pages, 1 Figure, 8 Tables

We explore the phenomenology of the full General Gauge Mediation parameter space in the MSSM focusing on the consequences of having a fundamental Higgs around 125 GeV. Assuming GUT-complete structure of the hidden sector, we allow for deviations from the strict definition of gauge mediated SUSY-breaking coming from mild violations of messenger-parity and from extra couplings between the Higgs multiplets and the hidden sector. Relaxing the GUT assumption, our parameter space is defined by the property of having vanishing A-terms at the messenger scale. In this extended setup we focus on the possibility of splitting the SU(3) mass parameters of GGM. In all these scenarios we investigate the possible spectra, discussing to what extent having an Higgs mass around 125 GeV is constraining the GGM parameter space and what are the possible signatures at LHC.

We study a Peccei-Quinn invariant extension of the next-to-minimal supersymmetric Standard Model (NMSSM), which turns out to be free from the tadpole and domain wall problems. Having a non-renormalizable coupling to the axion superfield, the SM singlet added to the Higgs sector can naturally generate an effective Higgs mu term around the weak scale. In the model, the lightest neutralino is dominated by the singlino, which gets a mass only through mixing with the neutral Higgsinos. We explore the phenomenological consequences resulting from the existence of such a relatively light neutralino. The coupling of the SM singlet to the Higgs doublets is constrained by the experimental bound on the invisible Z-boson decay width. Under this constraint, we examine the properties of the SM-like Higgs boson paying attention to its mass and decays. We also demonstrate a UV completion of the model in SU(5) grand unified theory with a missing-partner mechanism., 22 pages, 3 figures; published version

The E6 grand unified theory is an attractive candidate intermediate theory between the standard model and string theory. However, only one E6 grand unified model with three generations and at least one adjoint Higgs field has been derived from string theory in the literature, and this model is phenomenologically unsatisfactory. Recently, in arXiv:1012.1690, we have constructed two new such E6 grand unified models in heterotic asymmetric orbifolds. Although our new models themselves cannot resolve the unsatisfactory point in the previous model, our discovery raises hopes that one can construct many other such models in this framework and find better models. Here, by giving partition functions explicitly, we explain the details of our construction. Utilizing the lattice engineering technique and the diagonal embedding method, we can construct models systematically. We hope that these techniques and the details of our construction will lead to more phenomenologically desirable models., Comment: 42 pages, 2 figures, v2: text rearranged, version to appear in JHEP

We undertake a phenomenological study of SU(5) F-theory GUT models with an additional U(1)_{PQ} symmetry. In such models, breaking SU(5) with hypercharge flux leads to the presence of non-GUT multiplets in the spectrum. We study the effect these have on the unification of gauge couplings, including two-loop running as well as low- and high-scale threshold corrections. We use the requirement of unification to constrain the size of thresholds from KK modes of SU(5) gauge and matter fields. Assuming the non-GUT multiplets play the role of messengers of gauge mediation leads to controlled non-universalities in the sparticle spectrum while maintaining grand unification, and we study the LHC phenomenology of this scenario. We find that the MSSM spectrum may become compressed or stretched out {by up to a factor of three} depending on the distribution of hypercharge flux. We present a set of benchmark points whose production cross-sections and decays we investigate, and argue that precision kinematic edge measurements will allow the LHC to distinguish between our model and mGMSB., Comment: 46 pages, 15 figures