# J. Gunion - UniversityC. Davis

## Contact Details

NameJ. Gunion |
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AffiliationUniversityC. Davis |
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CityDavis |
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CountryUnited States |
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## Pubs By Year |
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## Pub CategoriesHigh Energy Physics - Phenomenology (50) High Energy Physics - Experiment (17) High Energy Physics - Theory (3) Cosmology and Nongalactic Astrophysics (3) Physics - Accelerator Physics (2) Nuclear Experiment (1) High Energy Astrophysical Phenomena (1) General Relativity and Quantum Cosmology (1) Physics - Instrumentation and Detectors (1) |

## Publications Authored By J. Gunion

Given the disappearance of the 750 GeV di-photon LHC signal and the absence of signals at high mass in this and other channels, significant constraints on the mixed Higgs-radion of the five-dimensional Randall-Sundrum model arise. By combining all channels, these constraints place a significant radion-mass-dependent lower bound on the radion vacuum expectation value that is fairly independent of the amount of Higgs radion mixing. Read More

In the alignment limit of a multi-doublet Higgs sector, one of the Higgs mass eigenstates aligns in field space with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM) Higgs boson. We consider CP-conserving Two-Higgs-Doublet Models (2HDMs) of Type I and Type II near the alignment limit in which the heavier of the two CP-even Higgs bosons, $H$, is the SM-like state observed with a mass of 125 GeV, and the couplings of $H$ to gauge bosons approach those of the SM. We review the theoretical structure and analyze the phenomenological implications of this particular realization of the alignment limit, where decoupling of the extra states cannot occur given that the lighter CP-even state $h$ must, by definition, have a mass below 125 GeV. Read More

We show that in a multi-Higgs model in which one Higgs fits the LHC 125 GeV state, one or more of the other Higgs bosons can mediate DM-nucleon interactions with maximal DM isospin violation being possible for appropriate Higgs-quark couplings, independent of the nature of DM. We then consider the explicit example of a Type II two-Higgs-doublet model, identifying the h or H as the 125 GeV state while the H or h, respectively, mediates DM-nucleon interactions. Finally, we show that if a stable scalar, S, is added then it can be a viable light DM candidate with correct relic density while obeying all direct and indirect detection limits. Read More

We present a 5D $\mathbb{Z}_2$-symmetric IR-UV-IR model with a {\it warped KK-parity} under which the bulk fields have towers of either even or odd KK-modes. We show that this $\mathbb{Z}_2$-symmetric geometry is equivalent to two times the UV-IR geometry (Randall-Sundrum model) provided each bulk field is subject to Neumann (or mixed) and Dirichlet boundary conditions at the UV-brane for even and odd fields, respectively. The 5D Standard Model (SM) bosonic sector is considered, such that in the 4D low-energy effective theory the $\mathbb{Z}_2$-even zero-modes correspond to the SM degrees of freedom, whereas the $\mathbb{Z}_2$-odd zero modes serve as a dark sector. Read More

We employ an $SU(2)$ bulk Higgs doublet as the stabilization field in Randall-Sundrum model with appropriate bulk and brane-localized potentials. The gauge hierarchy problem can be solved for an exponentially IR-localized Higgs background field with mild values of fundamental parameters of the 5D theory. We consider an IR-UV-IR background geometry with the 5D SM fields in the bulk such that all the fields have even and odd tower of KK-modes. Read More

In the alignment limit of a multi-doublet Higgs sector, one of the Higgs mass eigenstates aligns with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM) Higgs boson. We consider CP-conserving Two-Higgs-Doublet Models (2HDMs) of Type I and Type II near the alignment limit in which the lighter of the two CP-even Higgs bosons, $h$, is the SM-like state observed at 125 GeV. In particular, we focus on the 2HDM parameter regime where the coupling of $h$ to gauge bosons approaches that of the SM. Read More

**Authors:**Daniel Abercrombie, Nural Akchurin, Ece Akilli, Juan Alcaraz Maestre, Brandon Allen, Barbara Alvarez Gonzalez, Jeremy Andrea, Alexandre Arbey, Georges Azuelos, Patrizia Azzi, Mihailo Backović, Yang Bai, Swagato Banerjee, James Beacham, Alexander Belyaev, Antonio Boveia, Amelia Jean Brennan, Oliver Buchmueller, Matthew R. Buckley, Giorgio Busoni, Michael Buttignol, Giacomo Cacciapaglia, Regina Caputo, Linda Carpenter, Nuno Filipe Castro, Guillelmo Gomez Ceballos, Yangyang Cheng, John Paul Chou, Arely Cortes Gonzalez, Chris Cowden, Francesco D'Eramo, Annapaola De Cosa, Michele De Gruttola, Albert De Roeck, Andrea De Simone, Aldo Deandrea, Zeynep Demiragli, Anthony DiFranzo, Caterina Doglioni, Tristan du Pree, Robin Erbacher, Johannes Erdmann, Cora Fischer, Henning Flaecher, Patrick J. Fox, Benjamin Fuks, Marie-Helene Genest, Bhawna Gomber, Andreas Goudelis, Johanna Gramling, John Gunion, Kristian Hahn, Ulrich Haisch, Roni Harnik, Philip C. Harris, Kerstin Hoepfner, Siew Yan Hoh, Dylan George Hsu, Shih-Chieh Hsu, Yutaro Iiyama, Valerio Ippolito, Thomas Jacques, Xiangyang Ju, Felix Kahlhoefer, Alexis Kalogeropoulos, Laser Seymour Kaplan, Lashkar Kashif, Valentin V. Khoze, Raman Khurana, Khristian Kotov, Dmytro Kovalskyi, Suchita Kulkarni, Shuichi Kunori, Viktor Kutzner, Hyun Min Lee, Sung-Won Lee, Seng Pei Liew, Tongyan Lin, Steven Lowette, Romain Madar, Sarah Malik, Fabio Maltoni, Mario Martinez Perez, Olivier Mattelaer, Kentarou Mawatari, Christopher McCabe, Théo Megy, Enrico Morgante, Stephen Mrenna, Siddharth M. Narayanan, Andy Nelson, Sérgio F. Novaes, Klaas Ole Padeken, Priscilla Pani, Michele Papucci, Manfred Paulini, Christoph Paus, Jacopo Pazzini, Björn Penning, Michael E. Peskin, Deborah Pinna, Massimiliano Procura, Shamona F. Qazi, Davide Racco, Emanuele Re, Antonio Riotto, Thomas G. Rizzo, Rainer Roehrig, David Salek, Arturo Sanchez Pineda, Subir Sarkar, Alexander Schmidt, Steven Randolph Schramm, William Shepherd, Gurpreet Singh, Livia Soffi, Norraphat Srimanobhas, Kevin Sung, Tim M. P. Tait, Timothee Theveneaux-Pelzer, Marc Thomas, Mia Tosi, Daniele Trocino, Sonaina Undleeb, Alessandro Vichi, Fuquan Wang, Lian-Tao Wang, Ren-Jie Wang, Nikola Whallon, Steven Worm, Mengqing Wu, Sau Lan Wu, Hongtao Yang, Yong Yang, Shin-Shan Yu, Bryan Zaldivar, Marco Zanetti, Zhiqing Zhang, Alberto Zucchetta

This document is the final report of the ATLAS-CMS Dark Matter Forum, a forum organized by the ATLAS and CMS collaborations with the participation of experts on theories of Dark Matter, to select a minimal basis set of dark matter simplified models that should support the design of the early LHC Run-2 searches. A prioritized, compact set of benchmark models is proposed, accompanied by studies of the parameter space of these models and a repository of generator implementations. This report also addresses how to apply the Effective Field Theory formalism for collider searches and present the results of such interpretations. Read More

We construct a 5D $\mathbb{Z}_2$-symmetric model with three D3-branes: two IR ones with negative tension located at the ends of an extra-dimensional interval and a UV-brane with positive tension placed in the middle of the interval -- IR-UV-IR model. The background solutions for this geometric setup are found without and with taking into account the backreaction of the matter fields. A 5D $SU(2)$ Higgs doublet is employed as the Goldberger-Wise stabilizing field in this geometry and solutions of the 5D coupled scalar-gravity equations are found by using the superpotential method. Read More

We explore the possibilities in two-Higgs-doublet models (2HDMs) of Type I and Type II for Higgs states with mass below about 60 GeV, i.e. less than half of the ~125 GeV mass of the observed SM-like Higgs boson. Read More

A sign change in the Higgs couplings to fermions and massive gauge bosons is still allowed in the framework of two-Higgs doublet models (2HDM). In this work we discuss the possible sign changes in the Higgs couplings to fermions and gauge bosons, while reviewing the status of the 8-parameter CP-conserving 2HDM after the Large Hadron Collider 8 TeV run. Read More

We update the constraints on Two-Higgs-Doublet Models of Type I and II discussed in arXiv:1405.3584 using the latest LHC measurements of the ~125.5 GeV Higgs signal as of Summer 2014. Read More

We extend the two-Higgs doublet models of Type I and Type II by adding a real gauge-singlet scalar S dark matter candidate (2HDMS models). We impose theoretical constraints deriving from perturbativity, stability, unitarity and correct electroweak symmetry breaking and require that the lightest CP-even Higgs, h, fit the LHC data for the $\sim 125.5$ GeV state at the $68\%$~C. Read More

We confront the most common CP-conserving 2HDM with the LHC data analysed so far while taking into account all previously available experimental data. A special allowed corner of the parameter space is analysed - the so-called wrong-sign scenario where the Higgs coupling to down-type quarks changes sign relative to the Standard Model while the coupling to the massive vector bosons does not. Read More

We analyze the Two-Higgs-Doublet Models (2HDMs) of Type I and II for consistency with the latest measurements of the ~125.5 GeV Higgs-like signal at the LHC. To this end, we perform scans of the 2HDM parameter space taking into account all relevant pre-LHC constraints as well as the most recent limits coming from searches for heavy Higgs-like states at the LHC. Read More

**Authors:**G. Brooijmans

^{1}, R. Contino

^{2}, B. Fuks

^{3}, F. Moortgat

^{4}, P. Richardson

^{5}, S. Sekmen

^{6}, A. Weiler

^{7}, A. Alloul, A. Arbey, J. Baglio, D. Barducci, A. J. Barr, L. Basso, M. Battaglia, G. Bélanger, A. Belyaev, J. Bernon, A. Bharucha, O. Bondu, F. Boudjema, E. Boos, M. Buchkremer, V. Bunichev, G. Cacciapaglia, G. Chalons, E. Conte, M. J. Dolan, A. Deandrea, K. De Causmaecker, A. Djouadi, B. Dumont, J. Ellis, C. Englert, A. Falkowski, S. Fichet, T. Flacke, A. Gaz, M. Ghezzi, R. Godbole, A. Goudelis, M. Gouzevitch, D. Greco, R. Grober, C. Grojean, D. Guadagnoli, J. F. Gunion, B. Herrmann, J. Kalinowski, J. H. Kim, S. Kraml, M. E. Krauss, S. Kulkarni, S. J. Lee, S. H. Lim, D. Liu, F. Mahmoudi, Y. Maravin, A. Massironi, L. Mitzka, K. Mohan, G. Moreau, M. M. Mühlleitner, D. T. Nhung, B. O'Leary, A. Oliveira, L. Panizzi, D. Pappadopulo, S. Pataraia, W. Porod, A. Pukhov, F. Riva, J. Rojo, R. Rosenfeld, J. Ruiz-Álvarez, H. Rzehak, V. Sanz, D. Sengupta, M. Spannowsky, M. Spira, J. Streicher, N. Strobbe, A. Thamm, M. Thomas, R. Torre, W. Waltenberger, K. Walz, A. Wilcock, A. Wulzer, F. Würthwein, C. Wymant

**Affiliations:**

^{1}convenors,

^{2}convenors,

^{3}convenors,

^{4}convenors,

^{5}convenors,

^{6}convenors,

^{7}convenors

**Category:**High Energy Physics - Phenomenology

We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 3--21 June, 2013). Our report includes new computational tool developments, studies of the implications of the Higgs boson discovery on new physics, important signatures for searches for natural new physics at the LHC, new studies of flavour aspects of new physics, and assessments of the interplay between direct dark matter searches and the LHC. Read More

We consider the two-Higgs-doublet model as a framework in which to evaluate the viability of scenarios in which the sign of the coupling of the observed Higgs boson to down-type fermions (in particular, $b$-quark pairs) is opposite to that of the Standard Model (SM), while at the same time all other tree-level couplings are close to the SM values. We show that, whereas such a scenario is consistent with current LHC observations, both future running at the LHC and a future $e^+ e^-$ linear collider could determine the sign of the Higgs coupling to $b$-quark pairs. Discrimination is possible for two reasons. Read More

The parameter space of the phenomenological MSSM (pMSSM) is explored by means of Markov Chain Monte Charlo (MCMC) methods, taking into account the latest LHC results on the Higgs signal at 125 GeV in addition to relevant low-energy observables and LEP constraints. We use a Bayesian approach to derive posterior densities for the parameters and observables of interests. We find in particular that the Higgs measurements have a significant impact on the parameters mu and tan beta due to radiative corrections to the bottom Yukawa coupling. Read More

**Authors:**Yuri Alexahin, Charles M. Ankenbrandt, David B. Cline, Alexander Conway, Mary Anne Cummings, Vito Di Benedetto, Estia Eichten, Corrado Gatto, Benjamin Grinstein, Jack Gunion, Tao Han, Gail Hanson, Christopher T. Hill, Fedor Ignatov, Rolland P. Johnson, Valeri Lebedev, Ron Lipton, Zhen Liu, Tom Markiewicz, Anna Mazzacane, Nikolai Mokhov, Sergei Nagaitsev, David Neuffer, Mark Palmer, Milind V. Purohit, Rajendran Raja, Sergei Striganov, Don Summers, Nikolai Terentiev, Hans Wenzel

We propose the construction of, and describe in detail, a compact Muon Collider s-channel Higgs Factory. Read More

**Authors:**Yuri Alexahin, Charles M. Ankenbrandt, David B. Cline, Alexander Conway, Mary Anne Cummings, Vito Di Benedetto, Estia Eichten, Jean-Pierre Delahaye, Corrado Gatto, Benjamin Grinstein, Jack Gunion, Tao Han, Gail Hanson, Christopher T. Hill, Fedor Ignatov, Rolland P. Johnson, Valeri Lebedev, Leon M. Lederman, Ron Lipton, Zhen Liu, Tom Markiewicz, Anna Mazzacane, Nikolai Mokhov, Sergei Nagaitsev, David Neuffer, Mark Palmer, Milind V. Purohit, Rajendran Raja, Carlo Rubbia, Sergei Striganov, Don Summers, Nikolai Terentiev, Hans Wenzel

We propose the construction of a compact Muon Collider Higgs Factory. Such a machine can produce up to \sim 14,000 at 8\times 10^{31} cm^-2 sec^-1 clean Higgs events per year, enabling the most precise possible measurement of the mass, width and Higgs-Yukawa coupling constants. Read More

We put forth conclusions and suggestions regarding the presentation of the LHC Higgs results that may help to maximize their impact and their utility to the whole High Energy Physics community. Read More

The most recent LHC data have provided a considerable improvement in the precision with which various Higgs production and decay channels have been measured. Using all available public results from ATLAS, CMS and the Tevatron, we derive for each final state the combined confidence level contours for the signal strengths in the (gluon fusion + ttH associated production) versus (vector boson fusion + VH associated production) space. These "combined signal strength ellipses" can be used in a simple, generic way to constrain a very wide class of New Physics models in which the couplings of the Higgs boson deviate from the Standard Model prediction. Read More

We analyze the extent to which the LHC and Tevatron results as of the end of 2012 constrain invisible (or undetected) decays of the Higgs boson-like state at ~ 125 GeV. To this end we perform global fits for several cases: 1) a Higgs boson with Standard Model (SM) couplings but additional invisible decay modes; 2) SM couplings to fermions and vector bosons, but allowing for additional new particles modifying the effective Higgs couplings to gluons and photons; 3) no new particles in the loops but tree-level Higgs couplings to the up-quarks, down-quarks and vector bosons, relative to the SM, treated as free parameters. We find that in the three cases invisible decay rates of 23%, 61%, 88%, respectively, are consistent with current data at 95% confidence level (CL). Read More

Performing a fit to all publicly available data, we analyze the extent to which the latest results from the LHC and Tevatron constrain the couplings of the Higgs boson-like state at ~ 125 GeV. To this end we assume that only Standard Model (SM) particles appear in the Higgs decays, but tree-level Higgs couplings to the up-quarks, down-quarks and vector bosons, relative to the SM are free parameters. We also assume that the leptonic couplings relative to the SM are the same as for the down-quark, and a custodial symmetry for the V=W,Z couplings. Read More

We examine the level of enhancement that can be achieved in the ZZ and \gamma\gamma channels for a two-Higgs-doublet model Higgs boson (either the light h or the heavy H) with mass near 125 GeV after imposing all constraints from LEP data, B physics, precision electroweak data, vacuum stability, unitarity and perturbativity. The latter constraints restrict substantially the possibilities for enhancing the gg -> h -> \gamma\gamma or gg -> H -> \gamma\gamma signal relative to that for the SM Higgs, hSM. Further, we find that a significant enhancement of the gg -> h -> \gamma\gamma or gg -> H -> \gamma\gamma signal in Type II models is possible only if the gg -> h -> ZZ or gg -> H -> ZZ mode is even more enhanced, a situation disfavored by current data. Read More

We discuss NMSSM scenarios in which the lightest Higgs boson $h_1$ is consistent with the small LEP excess at about 98 GeV in $e^+e^- \to Zh$ with $h\to b\anti b$ and the heavier Higgs boson $h_2$ has the primary features of the LHC Higgs-like signals at 125 GeV, including an enhanced $\gamma\gamma$ rate. Verification or falsification of the 98 GeV $h_1$ may be possible at the LHC during the 14 TeV run. The detection of the other NMSSM Higgs bosons at the LHC and future colliders is also discussed, as well as dark matter properties of the scenario under consideration. Read More

The best fit to the Tevatron results in the bb channel and the mild excesses at CMS in the gamma-gamma channel at 136 GeV and in the tau-tau channel above 132 GeV can be explained by a second Higgs state in this mass range, in addition to the one at 125 GeV recently discovered at the LHC. We show that a scenario with two Higgs bosons at 125 GeV and 136 GeV can be consistent with practically all available signal rates, including a reduced rate in the tau-tau channel around 125 GeV as reported by CMS. An example in the parameter space of the general NMSSM is given where, moreover, the signal rates of the 125 GeV Higgs boson in the gamma-gamma channels are enhanced relative to the expectation for a SM Higgs boson of this mass. Read More

We develop diagnostic tools that would provide incontrovertible evidence for the presence of more than one Higgs boson near 125 GeV in the LHC data. Read More

We examine GUT-scale NMSSM scenarios in which {\it both} $h_1$ and $h_2$ lie in the 123 -- 128 GeV mass range. Very substantially enhanced $\gamma\gamma$ and other rates are possible. Broadened mass peaks are natural. Read More

**Authors:**S. Kraml

^{1}, B. C. Allanach

^{2}, M. Mangano

^{3}, H. B. Prosper

^{4}, S. Sekmen

^{5}, C. Balazs, A. Barr, P. Bechtle, G. Belanger, A. Belyaev, K. Benslama, M. Campanelli, K. Cranmer, A. De Roeck, M. J. Dolan, T. Eifert, J. R. Ellis, M. Felcini, B. Fuks, D. Guadagnoli, J. F. Gunion, S. Heinemeyer, J. Hewett, A. Ismail, M. Kadastik, M. Kramer, J. Lykken, F. Mahmoudi, S. P. Martin, T. Rizzo, T. Robens, M. Tytgat, A. Weiler

**Affiliations:**

^{1}editors,

^{2}editors,

^{3}editors,

^{4}editors,

^{5}editors

We present a set of recommendations for the presentation of LHC results on searches for new physics, which are aimed at providing a more efficient flow of scientific information between the experimental collaborations and the rest of the high energy physics community, and at facilitating the interpretation of the results in a wide class of models. Implementing these recommendations would aid the full exploitation of the physics potential of the LHC. Read More

**Authors:**G. Brooijmans, B. Gripaios, F. Moortgat, J. Santiago, P. Skands, D. Albornoz Vásquez, B. C. Allanach, A. Alloul, A. Arbey, A. Azatov, H. Baer, C. Balázs, A. Barr, L. Basso, M. Battaglia, P. Bechtle, G. Bélanger, A. Belyaev, K. Benslama, L. Bergström, A. Bharucha, C. Boehm, M. Bondarenko, O. Bondu, E. Boos, F. Boudjema, T. Bringmann, M. Brown, V. Bunichev, S. Calvet, M. Campanelli, A. Carmona, D. G. Cerdeño, M. Chala, R. S. Chivukula, D. Chowdhury, N. D. Christensen, M. Cirelli, S. Cox, K. Cranmer, J. Da Silva, T. Delahaye, A. De Roeck, A. Djouadi, E. Dobson, M. Dolan, F. Donato, G. Drieu La Rochelle, G. Duda, C. Duhr, B. Dumont, J. Edsjö, J. Ellis, C. Evoli, A. Falkowski, M. Felcini, B. Fuks, E. Gabrielli, D. Gaggero, S. Gascon-Shotkin, D. K. Ghosh, A. Giammanco, R. M. Godbole, P. Gondolo, T. Goto, D. Grasso, P. Gris, D. Guadagnoli, J. F. Gunion, U. Haisch, L. Hartgring, S. Heinemeyer, M. Hirsch, J. Hewett, A. Ismail, T. Jeltema, M. Kadastik, M. Kakizaki, K. Kannike, S. Khalil, J-L. Kneur, M. Krämer, S. Kraml, S. Kreiss, J. Lavalle, R. Leane, J. Lykken, L. Maccione, F. Mahmoudi, M. Mangano, S. P. Martin, D. Maurin, G. Moreau, S. Moretti, I. Moskalenko, G. Moultaka, M. Muhlleitner, I. Niessen, B. O'Leary, E. Orlando, P. Panci, G. Polesello, W. Porod, T. Porter, S. Profumo, H. Prosper, A. Pukhov, A. Racioppi, M. Raidal, M. Rausch de Traubenberg, A. Renaud, J. Reuter, T. G. Rizzo, T. Robens, A. Y. Rodríguez-Marrero, P. Salati, C. Savage, P. Scott, S. Sekmen, A. Semenov, C. -L. Shan, C. Shepherd-Themistocleous, E. H. Simmons, P. Slavich, C. Speckner, F. Staub, A. Strong, R. Taillet, F. S. Thomas, M. C. Thomas, I. Tomalin, M. Tytgat, M. Ughetto, L. Valéry, D. G. E. Walker, A. Weiler, S. M. West, C. D. White, A. J. Williams, A. Wingerter, C. Wymant, J. -H. Yu, C. -P. Yuan, D. Zerwas

We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies. Read More

**Affiliations:**

^{1}Warsaw,

^{2}UC Davis,

^{3}Concordia University

We explore the parameter choices in the five-dimensional Randall-Sundrum model with the inclusion of Higgs-radion mixing that can describe current LHC hints for one or more Higgs boson signals. Read More

We assess the extent to which various constrained versions of the NMSSM are able to describe the recent hints of a Higgs signal at the LHC corresponding to a Higgs mass in the range 123-128 GeV. Read More

We define benchmark models for SUSY searches at the LHC, including the CMSSM, NUHM, mGMSB, mAMSB, MM-AMSB and p19MSSM, as well as models with R-parity violation and the NMSSM. Within the parameter spaces of these models, we propose benchmark subspaces, including planes, lines and points along them. The planes may be useful for presenting results of the experimental searches in different SUSY scenarios, while the specific benchmark points may serve for more detailed detector performance tests and comparisons. Read More

We show that a $Wjj$ excess in Tevatron data could be explained in the context of the standard non-supersymmetric two-Higgs-doublet model for appropriately chosen parameters. Correlated signals in the $\gamma\gamma$ and $W^+ W^- b \anti b$ final states are predicted and are on the verge of being detectable. The proposed model is most attractive if the cross section for the $Wjj$ excess is $\lsim 1-2\pb$. Read More

We consider the impact of a 4th generation on Higgs to $\gamma\gamma$ and $WW,ZZ$ signals and demonstrate that the Tevatron and LHC have essentially eliminated the possibility of a 4th generation if the Higgs is SM-like and has mass below 200 GeV. We also show that the absence of enhanced Higgs signals in current data sets in the $\gamma\gamma$ and $WW,ZZ$ final states can strongly constrain the possibility of a 4th generation in two-Higgs-doublet models of type II, including the MSSM. Read More

**Authors:**Daniele Alves

^{1}, Nima Arkani-Hamed

^{2}, Sanjay Arora

^{3}, Yang Bai

^{4}, Matthew Baumgart

^{5}, Joshua Berger

^{6}, Matthew Buckley

^{7}, Bart Butler

^{8}, Spencer Chang

^{9}, Hsin-Chia Cheng

^{10}, Clifford Cheung

^{11}, R. Sekhar Chivukula

^{12}, Won Sang Cho

^{13}, Randy Cotta

^{14}, Mariarosaria D'Alfonso

^{15}, Sonia El Hedri

^{16}, Rouven Essig

^{17}, Jared A. Evans

^{18}, Liam Fitzpatrick

^{19}, Patrick Fox

^{20}, Roberto Franceschini

^{21}, Ayres Freitas

^{22}, James S. Gainer

^{23}, Yuri Gershtein

^{24}, Richard Gray

^{25}, Thomas Gregoire

^{26}, Ben Gripaios

^{27}, Jack Gunion

^{28}, Tao Han

^{29}, Andy Haas

^{30}, Per Hansson

^{31}, JoAnne Hewett

^{32}, Dmitry Hits

^{33}, Jay Hubisz

^{34}, Eder Izaguirre

^{35}, Jared Kaplan

^{36}, Emanuel Katz

^{37}, Can Kilic

^{38}, Hyung-Do Kim

^{39}, Ryuichiro Kitano

^{40}, Sue Ann Koay

^{41}, Pyungwon Ko

^{42}, David Krohn

^{43}, Eric Kuflik

^{44}, Ian Lewis

^{45}, Mariangela Lisanti

^{46}, Tao Liu

^{47}, Zhen Liu

^{48}, Ran Lu

^{49}, Markus Luty

^{50}, Patrick Meade

^{51}, David Morrissey

^{52}, Stephen Mrenna

^{53}, Mihoko Nojiri

^{54}, Takemichi Okui

^{55}, Sanjay Padhi

^{56}, Michele Papucci

^{57}, Michael Park

^{58}, Myeonghun Park

^{59}, Maxim Perelstein

^{60}, Michael Peskin

^{61}, Daniel Phalen

^{62}, Keith Rehermann

^{63}, Vikram Rentala

^{64}, Tuhin Roy

^{65}, Joshua T. Ruderman

^{66}, Veronica Sanz

^{67}, Martin Schmaltz

^{68}, Stephen Schnetzer

^{69}, Philip Schuster

^{70}, Pedro Schwaller

^{71}, Matthew D. Schwartz

^{72}, Ariel Schwartzman

^{73}, Jing Shao

^{74}, Jessie Shelton

^{75}, David Shih

^{76}, Jing Shu

^{77}, Daniel Silverstein

^{78}, Elizabeth Simmons

^{79}, Sunil Somalwar

^{80}, Michael Spannowsky

^{81}, Christian Spethmann

^{82}, Matthew Strassler

^{83}, Shufang Su

^{84}, Tim Tait

^{85}, Brooks Thomas

^{86}, Scott Thomas

^{87}, Natalia Toro

^{88}, Tomer Volansky

^{89}, Jay Wacker

^{90}, Wolfgang Waltenberger, Itay Yavin, Felix Yu, Yue Zhao, Kathryn Zurek

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^{1}Editor,

^{2}Editor,

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This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Read More

We examine the extent to which it is possible to realize the NMSSM "ideal Higgs" models espoused in several papers by Gunion et al in the context of partially universal GUT scale boundary conditions. To this end we use the powerful methodology of nested sampling. We pay particular attention to whether ideal-Higgs-like points not only pass LEP constraints but are also acceptable in terms of the numerous constraints now available, including those from the Tevatron and $B$-factory data, $(g-2)_\mu$ and the relic density $\Omega h^2$. Read More

**Affiliations:**

^{1}U.C. Davis

Recent data from CoGeNT and DAMA are roughly consistent with a very light dark matter particle with $m\sim 4-10\gev$ and spin-independent cross section of order $\sigma_{SI} \sim (1-3)\times 10^{-4}\pb$. An important question is whether these observations are compatible with supersymmetric models obeying $\Omega h^2\sim 0.11$ without violating existing collider constraints and precision measurements. Read More

**Affiliations:**

^{1}UC, Davis,

^{2}Chicago,

^{3}Fermilab and Chicago

**Category:**High Energy Physics - Phenomenology

We assess the extent to which the NMSSM can allow for light dark matter in the $2\gev\lsim \mcnone\lsim 12\gev$ mass range with correct relic density and large spin-independent direct-detection cross section, $\sigsi$, in the range suggested by \cogent\ and DAMA. For standard assumptions regarding nucleon $s$-quark content and cosmological relic density, $\rho$, we find that the NMSSM falls short by a factor of about 10 to 15 (3 to 5) without (with) significant violation of the current $(g-2)_\mu$ constraints. Read More

Recent observations by the CoGeNT collaboration (as well as long standing observations by DAMA/LIBRA) suggest the presence of a $\sim 5$-10 GeV dark matter particle with a somewhat large elastic scattering cross section with nucleons ($\sigma\sim 10^{-40}$ cm$^2$).Within the context of the minimal supersymmetric standard model (MSSM), neutralinos in this mass range are not able to possess such large cross sections, and would be overproduced in the early universe. Simple extensions of the MSSM, however, can easily accommodate these observations. Read More

**Affiliations:**

^{1}U. Indiana,

^{2}U.C. Davis and CERN

Recent BaBar limits on $\br(\Upsilon(3S)\to \gam a\to \gam \tau^+\tau^-)$ and
$\br(\Upsilon(3S)\to \gam a\to \gam \mu^+\mu^-)$ provide increased constraints
on the $a b\anti b$ coupling of a CP-odd Higgs boson, $a$, with
$m_a

We show that the existing CDF $L=630 pb^{-1}$ Tevatron data on $pp\to \mu^+\mu^- + X$ places substantial limits on a light CP-odd Higgs boson $a$ with $m_a<2m_B$ produced via $gg\to a$, even for $m_a>2m_\tau$ for which $BR(a\to \mu^+\mu^-)$ is relatively small. Extrapolation of this existing CDF analysis to $L=10 fb^{-1}$ suggests that Tevatron limits on the $a b\anti b$ coupling strength in the region $m_a>8\gev$ could be comparable to or better than limits from Upsilon decays in the $m_a<7\gev$ region. We also give rough estimates of future prospects at the LHC, demonstrating that early running will substantially improve limits on a light $a$ (or perhaps discover a signal). Read More

**Authors:**A. De Roeck, J. Ellis, C. Grojean, S. Heinemeyer, K. Jakobs, G. Weiglein, J. Wells, G. Azuelos, S. Dawson, B. Gripaios, T. Han, J. Hewett, M. Lancaster, C. Mariotti, F. Moortgat, G. Moortgat-Pick, G. Polesello, S. Riemann, M. Schumacher, K. Assamagan, P. Bechtle, M. Carena, G. Chachamis, K. F. Chen, S. De Curtis, K. Desch, M. Dittmar, H. Dreiner, M. Dührssen, B. Foster, M. T. Frandsen, A. Giammanco, R. Godbole, P. Govoni, J. Gunion, W. Hollik, W. S. Hou, G. Isidori, A. Juste, J. Kalinowski, A. Korytov, E. Kou, S. Kraml, M. Krawczyk, A. Martin, D. Milstead, V. Morton-Thurtle, K. Moenig, B. Mele, E. Ozcan, M. Pieri, T. Plehn, L. Reina, E. Richter-Was, T. Rizzo, K. Rolbiecki, F. Sannino, M. Schram, J. Smillie, S. Sultansoy, J. Tattersall, P. Uwer, B. Webber, P. Wienemann

Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300/fb of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10/fb of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. Read More

**Affiliations:**

^{1}UC Davis,

^{2}UC Davis,

^{3}UC Davis,

^{4}CERN

**Category:**High Energy Physics - Phenomenology

We discuss kinematic methods for determining the masses of the particles in events at a hadron collider in which a pair of identical particles is produced with each decaying via a series of on-shell intermediate beyond-the-SM (BSM) particles to visible SM particles and an invisible particle (schematically, pp -> ZZ + jets with Z -> Aa -> Bba -> Ccba -> ... Read More

**Affiliations:**

^{1}University of Florence,

^{2}U.C. Davis

**Category:**High Energy Physics - Phenomenology

We recompute the invisible Higgs decay width arising from Higgs-graviscalar mixing in the ADD model, comparing the original derivation in the non-diagonal mass basis to that in a diagonal mass basis. The results obtained are identical (and differ by a factor of 2 from the original calculation) but the diagonal-basis derivation is pedagogically useful for clarifying the physics of the invisible width from mixing. We emphasize that both derivations make it clear that a direct scan in energy for a process such as $WW\to WW$ mediated by Higgs plus graviscalar intermediate resonances would follow a {\it single} Breit-Wigner form with total width given by $\Gamma^{tot}=\Gamma_h^{SM}+\Gamma_{invisible}$. Read More

The next-to-minimal supersymmetric model with a light doublet-like CP-odd Higgs boson and small $\tan \beta$ can satisfy all experimental limits on Higgs bosons even with light superpartners. In these scenarios, the two lightest CP-even Higgs bosons, $\hi$ and $\hii$, and the charged Higgs boson, $\hp$, can all be light enough to be produced at LEP and yet have decays that have not been looked for or are poorly constrained by existing collider experiments. The channel $\hi\to \ai\ai$ (where $\ai$ is the lightest CP-odd boson and has mass below $2m_b$) with $\ai\to \tau^+\tau^-$ or $2j$ is still awaiting LEP constraints for $\mhi>86\gev$ or $82\gev$, respectively. Read More

We amalgamate the many experimental limits on the $ab\anti b$ coupling of a light CP-odd Higgs boson, $a$, including model-dependence coming from the ratio of the $at\anti t$ to the $a b\anti b$ coupling. We then employ these limits to analyze the extent to which a light $a$ can make a significant contribution to the discrepancy, $\Delta a_\mu$, between the experimentally observed $a_\mu$ and that predicted by the standard model. In a "model-independent" framework and in the context of a general two-Higgs-doublet model this is a significant possibility. Read More

**Authors:**M. G. Albrow, R. B. Appleby, M. Arneodo, G. Atoian, I. L. Azhgirey, R. Barlow, I. S. Bayshev, W. Beaumont, L. Bonnet, A. Brandt, P. Bussey, C. Buttar, J. M. Butterworth, M. Carter, B. E. Cox, D. Dattola, C. Da Via, J. de Favereau, D. d'Enterria, P. De Remigis, A. De Roeck, E. A. De Wolf, P. Duarte, J. R. Ellis, B. Florins, J. R. Forshaw, J. Freestone, K. Goulianos, J. Gronberg, M. Grothe, J. F. Gunion, J. Hasi, S. Heinemeyer, J. J. Hollar, S. Houston, V. Issakov, R. M. Jones, M. Kelly, C. Kenney, V. A. Khoze, S. Kolya, N. Konstantinidis, H. Kowalski, H. E. Larsen, V. Lemaitre, S. -L. Liu, A. Lyapine, F. K. Loebinger, R. Marshall, A. D. Martin, J. Monk, I. Nasteva, P. Nemegeer, M. M. Obertino, R. Orava, V. O'Shea, S. Ovyn, A. Pal, S. Parker, J. Pater, A. -L. Perrot, T. Pierzchala, A. D. Pilkington, J. Pinfold, K. Piotrzkowski, W. Plano, A. Poblaguev, V. Popov, K. M. Potter, S. Rescia, F. Roncarolo, A. Rostovtsev, X. Rouby, M. Ruspa, M. G. Ryskin, A. Santoro, N. Schul, G. Sellers, A. Solano, S. Spivey, W. J. Stirling, D. Swoboda, M. Tasevsky, R. Thompson, T. Tsang, P. Van Mechelen, A. Vilela Pereira, S. J. Watts, M. R. M. Warren, G. Weiglein, T. Wengler, S. N. White, B. Winter, Y. Yao, D. Zaborov, A. Zampieri, M. Zeller, A. Zhokin

We present the FP420 R&D project, which has been studying the key aspects of the development and installation of a silicon tracker and fast-timing detectors in the LHC tunnel at 420 m from the interaction points of the ATLAS and CMS experiments. These detectors would measure precisely very forward protons in conjunction with the corresponding central detectors as a means to study Standard Model (SM) physics, and to search for and characterise New Physics signals. This report includes a detailed description of the physics case for the detector and, in particular, for the measurement of Central Exclusive Production, pp --> p + phi + p, in which the outgoing protons remain intact and the central system phi may be a single particle such as a SM or MSSM Higgs boson. Read More

Old and new ideas regarding Higgs physics are reviewed. We first summarize the quadratic divergence / hierarchy problem which strongly suggests that the SM Higgs sector will be supplemented by new physics at high scales. We next consider means for delaying the hierarchy problem of the SM Higgs sector to unexpectedly high scales. Read More

**Authors:**Hsin-Chia Cheng

^{1}, Dalit Engelhardt

^{2}, John F. Gunion

^{3}, Zhenyu Han

^{4}, Bob McElrath

^{5}

**Affiliations:**

^{1}U.C. Davis,

^{2}Boston U.,

^{3}U.C. Davis,

^{4}U.C. Davis,

^{5}CERN

**Category:**High Energy Physics - Phenomenology

Many beyond the Standard Model theories include a stable dark matter candidate that yields missing / invisible energy in collider detectors. If observed at the Large Hadron Collider, we must determine if its mass and other properties (and those of its partners) predict the correct dark matter relic density. We give a new procedure for determining its mass with small error. Read More