Supersymmetric particle and Higgs boson masses from the landscape: Dynamical versus spontaneous supersymmetry breaking
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Results for “HIGGS MODEL”
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Primary observables for indirect searches at colliders
We consider the complete set of observables for collider searches for indirect effects of new heavy physics. They consist of SU(3) C × U(1) EM invariant interaction terms/operators that parameterize deviations from the Standard Model. We show that, un der very general assumptions, the leading deviations from the Standard Model are given by a finite number of ‘primary’ operators, with the remaining operators given by ‘Mandelstam descendants’ whose effects are suppressed by powers of Mandelstam variables divided by the mass scale M of the heavy physics. We explicitly determine all 3 and 4-point primary operators relevant for Higgs signals at colliders by using the correspondence between on-shell amplitudes and independent operators. We give a detailed discussion of the methods used to obtain this result, including a new analytical method for determining the independent operators. The results are checked using the Hilbert series that counts independent operators. We also give a rough sketch of the phenomenology, including unitarity bounds on the interaction strengths and rough estimates of their importance for Higgs decays at the HL-LHC. These results motivate further exploration of Higgs decays to $Z\overline{f}f$, $W\overline{f}f'$, $γ\overline{f}f$, and $Zγγ$.
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Search for Resonant and Nonresonant Higgs Boson Pair Production in the b b ¯ τ + τ − Decay Channel in p p Collisions at s = 13 TeV with the ATLAS Detector
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Measurement of the $H \rightarrow \gamma \gamma $ and $H \rightarrow ZZ^* \rightarrow 4 \ell $ cross-sections in $pp$ collisions at $\sqrt{s}=13.6$ TeV with the ATLAS detector
The inclusive Higgs boson production crosssection is measured in the di-photon and the Z Z* → 4$\ell$ decay channels using 31.4 and 29.0 fb –1 of pp collision data respectively, collected with the ATLAS detector at a centreof-mass energy of $\sqrt{s}$ = 13.6 TeV. To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are σ fid,γγ = $76^{+14}_{–13}$ fb, and $σ_{\text{fid,4}\ell}$ = 2.80 ± 0.74 fb, in agreement with the corresponding Standard Model predictions of 67.6±3.7 fb and 3.67±0.19 fb. Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of σ (pp → H) = $67^{+12}_{–11}$ pb and 46±12 pb at 13.6 TeV from the di-photon and Z Z* → 4$\ell$ measurements respectively. The two measurements are combined into a total cross-section measurement of σ (pp → H) = 58.2±8.7 pb, to be compared with the Standard Model prediction of σ (pp → H) SM = 59.9 ± 2.6 pb.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Nasa's Land Remote Sensing Plans for the 1980's
Research since the launch of LANDSAT-1 has been primarily directed to the development of analysis techniques and to the conduct of applications studies designed to address resource information needs in the United States and in many other countries. The current measurement capabilities represented by MSS, TM, and SIR-A and B, coupled with the present level of remote sensing understanding and the state of knowledge in the discipline earth sciences, form the foundation for NASA's Land Processes Program. Science issues to be systematically addressed include: energy balance, hydrologic cycle, biogeochemical cycles, biological productivity, rock cycle, landscape development, geological and botanical associations, and land surface inventory, monitoring, and modeling. A global perspective is required for using remote sensing technology for problem solving or applications context. A successful model for this kind of activity involves joint research with a user entity where the user provides a test site and ground truth and NASA provides the remote sensing techniques to be tested.
Higg, H. C.↗
Novel QCD Phenomena at the LHC: The Ridge, Digluon-Initiated Subprocesses, Direct Reactions, Non-Universal Antishadowing, and Forward Higgs Production
I discuss a number of novel tests of QCD at the LHC, measurements which can illuminate fundamental features of hadron physics. I also review the “Principle of Maximum Conformality” (PMC) which systematically sets the renormalization scale order-by-order in pQCD, eliminating an unnecessary theoretical uncertainty. The PMC allows LHC experiments to test QCD much more precisely, and the sensitivity of LHC measurements to physics beyond the Standard Model is increased.
Phenomenology-HEP,HEPPH↗
Moduli Dark Matter and the Search for Its Decay Line using Suzaku X-Ray Telescope
Light scalar fields called moduli arise from a variety of different models involving supersymmetry and/or string theory; thus their existence is a generic prediction of leading theories for physics beyond the standard model. They also present a formidable, long-standing problem for cosmology. We argue that an anthropic solution to the moduli problem exists in the case of small moduli masses and that it automatically leads to dark matter in the form of moduli. The recent discovery of the 125 GeV Higgs boson implies a lower bound on the moduli mass of about a keV. This form of dark matter is consistent with the observed properties of structure formation, and it is amenable to detection with the help of x-ray telescopes. We present the results of a search for such dark matter particles using spectra extracted from the first deep x-ray observations of the Draco and Ursa Minor dwarf spheroidal galaxies, which are darkmatter- dominated systems with extreme mass-to-light ratios and low intrinsic backgrounds. No emission line is positively detected, and we set new constraints on the relevant new physics.
Kusenko, Alexander↗
Higgs and superparticle mass predictions from the landscape
Predictions for the scale of SUSY breaking from the string landscape go back at least a decade to the work of Denef and Douglas on the statistics of flux vacua. The assumption that an assortment of SUSY breaking F and D terms are present in the hidden sector, and their values are uniformly distributed in the landscape of D = 4, N = 1 effective supergravity models, leads to the expectation that the landscape pulls towards large values of soft terms favored by a power law behavior P(m soft )~m$n\atop{soft}$. On the other hand, similar to Weinberg’s prediction of the cosmological constant, one can assume an anthropic selection of weak scales not too far from the measured value characterized by mW,Z,h ~ 100 GeV. Working within a fertile patch of gravity-mediated low energy effective theories where the superpotential μ term is << m 3/2 , as occurs in models such as radiative breaking of Peccei-Quinn symmetry, this biases statistical distributions on the landscape by a cutoff on the parameter Δ EW , which measures fine-tuning in the m Z -μ mass relation. The combined effect of statistical and anthropic pulls turns out to favor low energy phenomenology that is more or less agnostic to UV physics. While a uniform selection n = 0 of soft terms produces too low a value for m h , taking n = 1 and 2 produce most probabilistically m h ~125 GeV for negative trilinear terms. For n ≥ 1, there is a pull towards split generations with m$\sim\atop{q}$,$\sim\atop{ℓ}$(1,2)~10-30 TeV whilst m$\sim\atop{t}$ 1 ~1-2 TeV. The most probable gluino mass comes in at ~ 3 - 4 TeV — apparently beyond the reach of HL-LHC (although the required quasi-degenerate higgsinos should still be within reach). We comment on consequences for SUSY collider and dark matter searches.
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A minimal supersymmetric E6 unified theory
We show explicitly that supersymmetric E 6 Grand Unified Theory with a Higgs sector consisting of {27+$\overline{27}$ + 351+ $\overline{351}$ + 78} 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. Here, 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.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Measuring the CP property of Higgs coupling to tau leptons in the VBF channel at the LHC
Here, we study the prospects of measuring the CP property of the Higgs (h) coupling to tau leptons using the vector boson fusion (VBF) production mode at the high-luminosity LHC. Utilizing the previously proposed angle between the planes spanned by the momentum vectors of the (π + π 0 ) and (π - π 0 ) pairs originating in τ ± decays as the CP-odd observable, we perform a detailed Monte Carlo analysis, taking into account the relevant standard model backgrounds, as well as detector resolution effects. We then found that excluding a pure CP-odd coupling hypothesis requires O(400 fb -1 ) luminosity at the 14TeV LHC, and values of the CP-mixing angle larger than about 25° can be excluded at 95% con fidence level using 3 ab -1 data. It is observed that the uncertainty in the angular resolution of the neutral pion momenta does not constitute a signifi cant hurdle. Achieving a signal to background ratio (S=B) close to one, while keeping a high enough signal yield required to study the angular distributions selects out VBF as a promising mode to probe the CP nature of the hττ coupling, with gluon fusion suffering from a low S=B, and the W ± h=Zh mode (with leptonically decaying W ± =Z) having a much smaller signal rate.
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Probing the Higgs boson CP properties in vector-boson fusion production in the H → τ + τ − channel with the ATLAS detector
The CP properties of the Higgs boson are studied in the vector-boson fusion production mode. The analysis exploits the decay mode of the Higgs boson into two τ-leptons using 140 fb −1 of proton-proton collision data at $\sqrt{s}$ = 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Results are obtained using the Optimal Observable method. CP-violating interactions between the Higgs boson and electroweak gauge bosons are considered in the effective field theory framework, with the interaction strength described in the HISZ basis by $\tilde{d}$, and in the Warsaw basis by c H$\tilde{W}$ , c H$\tilde{B}$ , and c H$\tilde{W}$B . No deviations relative to the Standard Model are observed, and limits are obtained on the strength parameters. The $\tilde{d}$ parameter is constrained to the interval [−0.012, 0.044] at the 95% confidence level while c H$\tilde{W}$ is constrained to [−0.24, 0.83], when considering both linear and quadratic effects of physics beyond the Standard Model.
Hadron-Hadron Scattering↗
Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV
Our searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and W, Z, and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy √s=8TeV with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 fb -1 . These observed event rates are in agreement with expectations from the standard model. Finally, these results probe charginos and neutralinos with masses up to 720 GeV, and sleptons up to 260 GeV, depending on the model details.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
String Theory, the Dark Sector, and the Hierarchy Problem
We discuss dark energy, dark matter and the hierarchy problem in the context of a general non-commutative formulation of string theory. In this framework dark energy is generated by the dynamical geometry of the dual spacetime while dark matter, on the other hand, comes from the degrees of freedom dual to the visible matter. This formulation of string theory is sensitive both to the IR and UV scales and the Higgs scale is radiatively stable by being a geometric mean of radiatively stable UV and IR scales. We also comment on various phenomenological signatures of this novel approach to dark energy, dark matter and the hierarchy problem. We find that this new view on the hierarchy problem is realized in a toy model based on a non-holomorphic deformation of the stringy cosmic string. Finally, we discuss a proposal for a new non-perturbative formulation of string theory, which sheds light on M theory and F theory, as well as on supersymmetry and holography.
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Measurement of the transverse momentum spectrum of the Higgs boson produced in pp collisions at $ \sqrt{s}=8 $ TeV using $H \to WW$ decays
The cross section for Higgs boson production in pp collisions is studied using the H → W$^{+}$W$^{−}$ decay mode, followed by leptonic decays of the W bosons to an oppositely charged electron-muon pair in the final state. The measurements are performed using data collected by the CMS experiment at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.4 fb$^{−1}$. The Higgs boson transverse momentum (p$_{T}$) is reconstructed using the lepton pair p$_{T}$ and missing p$_{T}$. The differential cross section times branching fraction is measured as a function of the Higgs boson p$_{T}$ in a fiducial phase space defined to match the experimental acceptance in terms of the lepton kinematics and event topology. The production cross section times branching fraction in the fiducial phase space is measured to be 39 ± 8 (stat) ± 9 (syst) fb. The measurements are found to agree, within experimental uncertainties, with theoretical calculations based on the standard model.
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The minimal SUSY B - L model: from the unification scale to the LHC
Here, this paper introduces a random statistical scan over the high-energy initial parameter space of the minimal SUSY B - L model — denoted as the B - L MSSM. Each initial set of points is renormalization group evolved 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 ~125 GeV. The subspace of initial parameters that satisfies all such constraints is presented, shown to be robust and to contain a wide range of different configurations of soft supersymmetry breaking masses. The low-energy predictions of each such “valid” point — such as the sparticle mass spectrum and, in particular, the LSP — are computed and then statistically analyzed over the full subspace of valid points. Finally, the amount of fine-tuning required is quantified and compared to the MSSM computed using an identical random scan. The B - L MSSM is shown to generically require less fine-tuninng.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Impact of damping on the superconducting gap dynamics induced by intense terahertz pulses
In this study, we investigate the interplay between coherent gap dynamics and damping in superconductors taken out of equilibrium by strong optical pulses with subgap terahertz frequencies. A semiphenomenological formalism is developed to include the damping within the electronic subsystem that arises from effects beyond Bardeen-Cooper-Schrieffer mean-field theory, such as interactions between Bogoliubov quasiparticles and decay of the Higgs mode. These processes, conveniently expressed as longitudinal T 1 and transverse T 2 relaxation times in the standard pseudospin language for superconductors, cause the gap amplitude to be suppressed after the pulse is turned off, but before the timescale where thermalization occurs due to coupling to the lattice. Lastly, we show that our model quantitatively captures the experimental gap dynamics reported here of NbN and Nb 3 Sn through the picosecond timescale.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Energetic neutrinos from heavy-neutralino annihilation in the Sun
Neutralinos may be captured in the sun and annihilated therein producing high-energy neutrinos. Present limits on the flux of such neutrinos from underground detectors such as IMB and Kamiokande 2 may be used to rule out certain supersymmetric dark matter candidates, while in many other supersymmetric models the rates are large enough that if neutralinos do reside in the galactic halo, observation of a neutrino signal may be possible in the near future. Neutralinos that are either nearly pure Higgsino or a Higgsino/gaugino combination are generally captured in the sun by coherent scattering off nuclei via exchange of the lightest Higgs boson. If the squark mass is not much greater than the neutralino mass, then capture of neutralinos that are primarily gaugino occurs predominantly by spin-dependent scattering off hydrogen in the sun. The neutrino signal from annihilation of WIMPs with masses in the range of 80 to 1000 GeV in the sun should generally be stronger than that from weakly interacting massive particle (WIMP) annihilation in the earth, and detection rates for mixed-state neutralinos are generally higher than those for Higgsinos or gauginos.
Kamionkowski, Marc↗
Kinetic mixing, dark photons and an extra dimension. Part I
Extra dimensions (ED) can provide a useful tool for model-building. In this paper we introduce a single, flat ED extension of the kinetic-mixing/dark photon (DP) portal for dark matter (DM) interactions with the Standard Model (SM) assuming a compactification ‘radius’ of order R-1 ~ 10-1000 MeV and examine the resulting modifications to and augmentation of the usual DP phenomenology. In the present scenario, both the DP and DM experience the full 5-D while the SM fields are constrained to lie on a 4-D brane at the boundary of the ED. Such a setup can naturally yield the observed value of the DM relic density and explain the required rough degeneracy of the DM and DP masses needed to obtain it. Gauge symmetry breaking can occur via boundary conditions without the introduction of an additional singlet Higgs scalar thus avoiding all constraints associated with the coupling of such a field to the usual SM Higgs field in 5-D. The self-consistency in the removal of the kinetic mixing terms is found to lead to a brane localized kinetic term for the 5-D gauge field on the SM brane. Multiple variations of this scenario are found to be possible which are consistent with current experimental constraints but which predict very different phenomenologies. In this paper, we discuss the case of a complex scalar 5-D DM field, consistent with constraints arising from the CMB, which may or may not obtain a vacuum expectation value (vev). This approach can lead to interesting and distinctive signatures while being constrained by a wide array of existing measurements but with the details being dependent upon the model specifics.
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