Search

We point out that a non-relativistic $\sim 2 $ GeV dark matter (DM) which interacts with visible matter through higher dimensional Rayleigh operators could explain the excess of "electron recoil" events recently observed by the Xenon1T collaboration. A DM scattering event results in a few keV photon that on average carries most of the deposited energy, while the nuclear recoil energy is only a subleading correction. Since the Xenon1T detector does not discriminate between electrons and photons, such events would be interpreted as excess of the keV electrons. Indirect constraints from dark matter annihilation are avoided for light mediators of ${\mathcal O}(10~{\rm MeV})$ that have sizable couplings to neutrinos. One loop induced spin-independent scattering in dark matter may soon lead to a confirmation signal or already excludes regions of viable parameter space for the Rayleigh DM model, depending on what the exact values of the unknown nonperturbative nuclear matrix elements are., 5 pages, 5 figures, discussion shortened, typos corrected

The proton radius puzzle has motivated several new experiments that aim to extract the proton charge radius and resolve the puzzle. Recently PRad, a new electron-proton scattering experiment at Jefferson Lab, reported a proton charge radius of $0.831\pm 0.007_\textnormal{statistical}\pm 0.012_\textnormal{systematic}$. The value was obtained by using a rational function model for the proton electric form factor. We perform a model-independent extraction using $z$-expansion of the proton charge radius from PRad data. We find that the model-independent statistical error is more than 50\% larger compared to the statistical error reported by PRad., 11 pages, 4 figures, references added, journal version

In 2010 the first extraction of the proton charge radius from muonic hydrogen was found be be five standard deviations away form the regular hydrogen value. Eight years later, this proton radius puzzle is still unresolved. One of the most promising avenues to resolve the puzzle is by a muon-proton scattering experiment called MUSE. The typical momenta of the muons in this experiment are of the order of the muon mass. In this energy regime the muons are relativistic but the protons are non-relativistic. The interaction between them can be described by QED-NRQED effective field theory. In a previous paper we have shown how QED-NRQED reproduces Rosenbluth scattering up to $1/M^2$, where $M$ is the proton mass, and relativistic scattering off a static potential at ${\cal O}(Z^2\alpha^2)$ and leading power in $M$. In this paper we determine the Wilson coefficients of the four-fermion contact interactions at ${\cal O}(Z^2\alpha^2)$ and power $1/M^2$. Surprisingly, we find that the coefficient of the spin-independent interaction vanishes, implying that MUSE will be sensitive mostly to the proton charge radius and not spin-independent two-photon exchange effects., Comment: 37 pages. v2: text and references added, journal version

cd. autorów: L. Cao48,‡, G. Caria145,‡, G. Casarosa57,‡, C. Cecchi56,‡,D. Cˇ ervenkov10,‡,M.-C. Chang22,‡, P. Chang92,‡, R. Cheaib146,‡, V. Chekelian83,‡, Y. Chen154,‡, B. G. Cheon28,‡, K. Chilikin77,‡, K. Cho70,‡, J. Choi14,‡, S.-K. Choi27,‡, S. Choudhury35,‡, D. Cinabro170,‡, L. M. Cremaldi146,‡, D. Cuesta47,‡, S. Cunliffe16,‡, N. Dash33,‡, E. de la Cruz Burelo9,‡, E. de Lucia52,‡, G. De Nardo54,‡, †Editor. ‡Belle II Collaborator. §Theory or external contributing author. M. De Nuccio16,‡, G. De Pietro59,‡, A. De Yta Hernandez9,‡, B. Deschamps129,‡, M. Destefanis60,‡, S. Dey116,‡, F.Di Capua54,‡, S.Di Carlo75,‡, J. Dingfelder129,‡, Z. Doležal10,‡, I. Domínguez Jiménez125,‡, T.V. Dong30,26,‡, D. Dossett145,‡, S. Duell129,‡, S. Eidelman6,96,77,‡, D. Epifanov6,96,‡, J. E. Fast100,‡, T. Ferber16,‡, S. Fiore18,‡, A. Fodor85,‡, F. Forti57,‡, A. Frey24,‡, O. Frost16,‡, B. G. Fulsom100,‡, M. Gabriel83,‡, N. Gabyshev6,96,‡, E. Ganiev61,‡, X. Gao3,‡, B. Gao23,‡, R. Garg101,‡, A. Garmash6,96,‡, V. Gaur169,‡, A. Gaz90,‡, T. Geßler65,‡, U. Gebauer24,‡, M. Gelb48,‡, A. Gellrich16,‡, D. Getzkow65,‡, R. Giordano54,‡, A. Giri35,‡, A. Glazov16,‡, B. Gobbo61,‡, R. Godang157,‡, O. Gogota110,‡, P. Goldenzweig48,‡, B. Golob141,109,‡,W. Gradl63,‡, E. Graziani59,‡, M. Greco60,‡, D. Greenwald114,‡, S. Gribanov6,96,‡, Y. Guan17,‡, E. Guido60,‡, A. Guo41,‡, S. Halder111,‡, K. Hara30,26,‡, O. Hartbrich138,‡, T. Hauth48,‡, K. Hayasaka94,‡, H. Hayashii91,‡, C. Hearty130,‡, I. Heredia De La Cruz9,‡, M. Hernandez Villanueva9,‡, A. Hershenhorn130,‡, T. Higuchi66,‡,M. Hoek63,‡, S. Hollitt124,‡, N. T. HongVan44,‡, C.-L. Hsu160,‡, Y. Hu41,‡, K. Huang92,‡, T. Iijima89,90,‡, K. Inami90,‡, G. Inguglia40,‡,A. Ishikawa119,‡, R. Itoh30,26,‡, Y. Iwasaki30,‡, M. Iwasaki97,‡, P. Jackson124,‡, W. W. Jacobs37,‡, I. Jaegle137,‡, H. B. Jeon73,‡, X. Ji41,‡, S. Jia3,‡,Y. Jin162,‡, C. Joo66,‡,M. Künzel16,‡, I. Kadenko110,‡, J. Kahn78,‡, H. Kakuno121,‡, A. B. Kaliyar36,‡, J. Kandra10,‡, K. H. Kang73,‡, Y. Kato90,‡, T. Kawasaki68,‡, C. Ketter138,‡, M. Khasmidatul143,‡, H. Kichimi30,‡, J. B. Kim71,‡, K. T. Kim71,‡, H. J. Kim73,‡, D.Y. Kim108,‡, K. Kim172,‡, Y. Kim172,‡, T. D. Kimmel169,‡, H. Kindo30,26,‡, K. Kinoshita135,‡, T. Konno68,‡, A. Korobov6,96,‡, S. Korpar144,109,‡, D. Kotchetkov138,‡, R. Kowalewski165,‡, P. Križan141,109,‡, R. Kroeger146,‡, J.-F. Krohn145,‡, P. Krokovny6,96,‡, W. Kuehn65,‡, T. Kuhr78,‡, R. Kulasiri67,‡, M. Kumar81,‡, R. Kumar101,‡, T. Kumita121,‡, A. Kuzmin6,96,‡, Y.-J. Kwon172,‡, S. Lacaprara55,‡, Y.-T. Lai30,‡, K. Lalwani81,‡, J. S. Lange65,‡, S. C. Lee73,‡, J.Y. Lee106,‡, P. Leitl83,‡, D. Levit114,‡, S. Levonian16,‡, S. Li3,‡, L. K. Li41,‡, Y. Li41,‡,Y. B. Li103,‡, Q. Li103,‡, L. Li Gioi83,‡, J. Libby36,‡, Z. Liptak138,‡, D. Liventsev169,‡, S. Longo165,‡, A. Loos158,‡, G. Lopez Castro9,‡, M. Lubej109,‡, T. Lueck57,‡, F. Luetticke129,‡, T. Luo23,‡, F. Müller16,‡, Th. Müller48,‡, C. MacQueen145,‡, Y. Maeda90,‡, M. Maggiora60,‡, S. Maity33,‡, E. Manoni56,‡, S. Marcello60,‡, C. Marinas129,‡, M. Martinez Hernandez4,‡, A. Martini59,‡, D. Matvienko6,96,77,‡, J. A. McKenna130,‡, F. Meier160,‡, M. Merola54,‡, F. Metzner48,‡, C. Miller165,‡, K. Miyabayashi91,‡, H. Miyake30,26,‡, H. Miyata94,‡, R. Mizuk77,88,87,‡, G. B. Mohanty111,163,‡, H. K. Moon71,‡, T. Moon106,‡,A. Morda55,‡, T. Morii66,‡, M. Mrvar109,‡, G. Muroyama90,‡, R. Mussa60,‡, I. Nakamura30,26,‡, T. Nakano99,‡, M. Nakao30,26,‡, H. Nakayama30,26,‡, H. Nakazawa92,‡, T. Nanut109,‡, M. Naruki72,‡, K. J. Nath34,‡, M. Nayak116,‡, N. Nellikunnummel151,‡, D. Neverov90,‡, C. Niebuhr16,‡, J. Ninkovic84,‡, S. Nishida30,26,‡, K. Nishimura138,‡, M. Nouxman143,‡, G. Nowak93,‡, K. Ogawa94,‡, Y. Onishchuk110,‡, H. Ono94,‡, Y. Onuki162,‡, P. Pakhlov77,88,‡, G. Pakhlova87,‡, B. Pal5,‡, E. Paoloni57,‡, H. Park73,‡, C.-S. Park172,‡, B. Paschen129,‡, A. Passeri59,‡, S. Paul114,‡, T. K. Pedlar80,‡, M. Perelló46,‡, I. M. Peruzzi52,‡, R. Pestotnik109,‡, L. E. Piilonen169,‡, L. Podesta Lerma125,‡, V. Popov87,‡, K. Prasanth111,‡, E. Prencipe21,‡, M. Prim48,‡, M. V. Purohit158,‡, A. Rabusov114,‡, R. Rasheed47,‡, S. Reiter65,‡, M. Remnev6,96,‡, P. K. Resmi36,‡, I. Ripp-Baudot47,‡, M. Ritter78,‡, M. Ritzert139,‡, G. Rizzo57,‡, L. Rizzuto141,109,‡, S. H. Robertson85,‡, D. Rodriguez Perez125,‡, J. M. Roney165,‡, C. Rosenfeld158,‡, A. Rostomyan16,‡, N. Rout36,‡, S. Rummel78,‡, G. Russo54,‡, D. Sahoo111,‡, Y. Sakai30,26,‡, M. Salehi143,78,‡, D. A. Sanders146,‡, S. Sandilya135,‡, A. Sangal135,‡, L. Santelj47,‡, J. Sasaki162,‡, Y. Sato30,‡, V. Savinov151,‡, B. Scavino63,‡, M. Schram100,‡, H. Schreeck24,‡, J. Schueler138,‡,C. Schwanda40,‡,A. J. Schwartz135,‡,R.M. Seddon85,‡,Y. Seino94,‡, K. Senyo171,‡, O. Seon90,‡, I. S. Seong138,‡, M. E. Sevior145,‡, C. Sfienti63,‡, M. Shapkin38,‡, C. P. Shen3,‡,M. Shimomura91,‡, J.-G. Shiu92,‡, B. Shwartz6,96,‡,A. Sibidanov165,‡, F. Simon83,113,‡, J. B. Singh101,‡, R. Sinha42,‡, S. Skambraks83,‡, K. Smith145,‡, R. J. Sobie165,‡, A. Soffer116,‡, A. Sokolov38,‡, E. Solovieva77,87,‡, B. Spruck63,‡, S. Staniˇc149,‡, M. Stariˇc109,‡, N. Starinsky147,‡, U. Stolzenberg24,‡, Z. Stottler169,‡, R. Stroili55,‡, J. F. Strube100,‡, J. Stypula93,‡, M. Sumihama25,‡, K. Sumisawa30,26,‡, T. Sumiyoshi121,‡, D. Summers146,‡, W. Sutcliffe48,‡, S. Y. Suzuki30,26,‡, M. Tabata13,‡, M. Takahashi16,‡, M. Takizawa107,‡, U. Tamponi60,‡, J. Tan145,‡, S. Tanaka30,26,‡, K. Tanida2,‡, N. Taniguchi30,‡, Y. Tao137,‡, P. Taras147,‡, G. Tejeda Munoz4,‡, F. Tenchini16,‡, U. Tippawan12,‡, E. Torassa55,‡, K. Trabelsi30,26,‡, T. Tsuboyama30,26,‡, M. Uchida120,‡, S. Uehara30,26,‡, T. Uglov77,87,‡, Y. Unno28,‡, S. Uno30,26,‡, Y. Ushiroda30,26,162,‡, Y. Usov6,96,‡, S. E. Vahsen138,‡, R. van Tonder48,‡, G. Varner138,‡, K. E. Varvell160,‡, A. Vinokurova6,96,‡, L.Vitale61,‡,M.Vos46,‡,A.Vossen17,‡,E.Waheed145,‡,H.Wakeling85,‡,K.Wan162,‡, M.-Z.Wang92,‡, X. L. Wang23,‡, B. Wang135,‡, A. Warburton85,‡, J. Webb145,‡, S. Wehle16,‡, C. Wessel129,‡, J. Wiechczynski93,‡, P. Wieduwilt24,‡, E. Won71,‡, Q. Xu41,‡, X. Xu41,‡, B. D. Yabsley160,‡, S. Yamada30,‡, H. Yamamoto119,‡, W. Yan3,‡, W. Yan154,‡, S. B. Yang71,‡, H. Ye16,‡, I. Yeo70,‡, J. H. Yin41,‡, M. Yonenaga121,‡, T. Yoshinobu94,‡, W. Yuan55,‡, C. Z. Yuan41,‡, Y. Yusa94,‡, S. Zakharov77,87,‡, L. Zani57,‡, M. Zeyrek86,‡, J. Zhang41,‡,Y. Zhang23,‡,Y. Zhang154,‡, X. Zhou3,‡, V. Zhukova77,‡, V. Zhulanov6,96,‡, and A. Zupanc141,109,‡ †Editor. ‡Belle II Collaborator. §Theory or external contributing author., "The Belle II Theory Interface Platform (B2TiP) was created as a physics prospects working group of the Belle II collaboration in June 2014. It offered a platform where theorists and experimentalists could work together to elucidate the potential impacts of the Belle II program, which includes a wide scope of physics topics: B physics, charm, τ , quarkonium physics, electroweak precision measurements, and dark sector searches. It is composed of nine working groups (WGs), which 6/654 Downloaded from https://academic.oup.com/ptep/article-abstract/2019/12/123C01/5685006 by Uniwersytet Slaski Biblioteka Glowna user on 20 February 2020 PTEP 2019, 123C01 E. Kou et al. are coordinated by teams of theory and experiment conveners: WG1, Semileptonic and leptonic B Decays; WG2, Radiative and Electroweak Penguins; WG3, φ1 and φ2 (Time-Dependent CP Violation) Measurements; WG4, φ3 Measurement; WG5, Charmless Hadronic B Decay; WG6, Charm; WG7, Quarkonium(-like); WG8, τ and Low-Multiplicity Processes; WG9, New Physics. We organized workshops twice a year from 2014 until 2016, which moved from KEK in Japan to Europe and the Americas, gathering experts in the respective fields for discussions with Belle II members. One of the goals for B2TiP was to propose so-called “golden and silver channels”: we asked each working group to choose, among numerous possible measurements, those that would have the highest potential impact and to focus on them for the writeup. Theorists scrutinized the role of those measurements in terms of understanding the theory behind them, and estimated the theoretical uncertainties now achievable as well as prospects for the future. For flavor physics, having tight control of hadronic uncertainties is one of the most crucial aspects in the field, and this is considered an important criterion in determining the golden or silver channels. Experimentalists, on the other hand, investigated the expected improvements with data from Belle II. For the channels where the errors are dominated by statistical uncertainties, or where systematic errors are reducible, the errors can decrease rapidly as more data becomes available. The impact of the upgraded performance from Belle II is a crucial element in reducing the uncertainties: we therefore include the latest available studies of the detector efficiency using Monte Carlo simulated events.We list the golden and silver channel table in the introductory chapter, as a guide for the chapters that follow. This book is not a collection of reports based on talks given at the workshops. The working group conveners endeavored to construct a coherent document that can be used by Belle II collaborators, and others in the field of flavor physics, as a reference. Two books of a similar type have been produced in the past: The BaBar Book [1] and The Physics of the B Factories [2]. In order to avoid too much repetition with respect to those references, we refer to them wherever possible for introductory material. We would like to thank the section editors and contributing authors for the many stimulating discussions and their tremendous efforts in bringing the book together." (Preface)

Effective field theories such as Heavy Quark Effective Theory (HQET) and Non Relativistic Quantum Chromo-(Electro-) dynamics NRQCD (NRQED) are indispensable tools in controlling the effects of the strong interaction. The increasing experimental precision requires the knowledge of higher dimensional operators. We present a general method that allows for an easy construction of HQET or NRQCD (NRQED) operators that contain two heavy quark or non-relativistic fields and any number of covariant derivatives. As an application of our method, we list these terms in the $1/M^4$ NRQCD Lagrangian, where $M$ is the mass of of the spin-half field., 28 pages, footnote added, journal version

Effective field theories such as Heavy Quark Effective Theory (HQET) are indispensable tools in controlling the effects of the strong interaction. The increasing experimental precision requires the knowledge of higher dimensional operators. We present a general method that allows for an easy construction of HQET operators that contain two heavy quarks and any number of covariant derivatives., 5 pages, updated version based on version 2 of arXiv:1702.08904 [hep-ph]

Many extension of the standard model contain an extra U(1)' gauge group with a heavy Z' gauge boson. Perhaps the most clear signal for such a Z' would be a resonance in the invariant mass spectrum of the lepton pairs to which it decays. In the absence of such a signal, experiments can set limits on the couplings of such a Z', using a standard formula from theory. We repeat its derivation and find that, unfortunately, the standard formula in the literature is a factor of 8 too small. We briefly explore the implication for existing experimental searches and encourage the high energy physics community to re-examine analyses that have used this formula., Comment: 9 pages, 1 figure, two references added, journal version

This talk discusses the effective field theory view of deep inelastic scattering. In such an approach, the standard factorization formula of a hard coefficient multiplied by a parton distribution function arises from matching of QCD onto an effective field theory. The DGLAP equations can then be viewed as the standard renormalization group equations that determines the cut-off dependence of the non-local operator whose forward matrix element is the parton distribution function. As an example, the non-singlet quark splitting functions is derived directly from the renormalization properties of the non-local operator itself. This approach, although discussed in the literature, does not appear to be well known to the larger high energy community. In this talk we give a pedagogical introduction to this subject., 11 pages, 1 figure, To appear in Modern Physics Letters A

The nucleon spin-averaged forward virtual Compton tensor determines important physical quantities such as electromagnetically-induced mass differences of nucleons, and two-photon exchange contributions in hydrogen spectroscopy. It depends on two kinematic variables: $\nu$, the virtual photon energy in the proton rest frame, and $Q^2$, the photon's invariant four-momentum squared. Using the operator product expansion, we calculate the tensor's large-$Q^2$ behavior for $\nu=0$, including for the first time the full spin-2 contribution and correcting a previous result in the literature for the spin-0 contribution. Implications for the proton radius puzzle are discussed., Comment: 23 pages, 11 figures. v2: journal version, typo in Eq.(15) corrected, Fig.11 updated with same inputs as Fig.10

The proton radius puzzle, i.e. the large discrepancy in the extraction of the proton charge radius between regular and muonic hydrogen, challenges our understanding of the structure of the proton. It can also be an indication of a new force that couples to muons, but not to electrons. An effective field theory analysis using Non Relativistic Quantum Electrodynamics (NRQED) indicates that the muonic hydrogen result can be interpreted as a large, compared to some model estimates, muon-proton spin-independent contact interaction. The muonic hydrogen result can be tested by a muon-proton scattering experiment, MUSE, that is planned at the Paul Scherrer Institute in Switzerland. The typical momenta of the muons in this experiment are of the order of the muon mass. In this energy regime the muons are relativistic but the protons are still non-relativistic. The interaction between the muons and protons can be described by a hybrid QED-NRQED effective field theory. We present some elements of this effective field theory. In particular we consider ${\cal O}(Z\alpha)$ scattering up to power $m^2/M^2$, where $m$ ($M$) is the muon (proton) mass and $Z=1$ for a proton, and ${\cal O}(Z^2\alpha^2)$ scattering at leading power. We show how the former reproduces Rosenbluth scattering up to power $m^2/M^2$ and the latter the relativistic scattering off a static potential. Proton structure corrections at ${\cal O}(Z^2\alpha^2)$ will be considered in a subsequent paper., Comment: 15 pages, 3 figures. v2: text and references added, journal version

Understanding the charged current quasielestic (CCQE) neutrino-nucleus interaction is important for precision studies of neutrino oscillations. The theoretical description of the interaction depends on the combination of a nuclear model with the knowledge of form factors. While the former has received considerable attention, the latter, in particular the axial form factor, is implemented using the historical dipole model. Instead, we use a model-independent approach, presented in a previous study, to analyze the muon antineutrino CCQE mineral oil data published by the MiniBooNE collaboration. We combine the cross section for scattering of antineutrinos off protons in carbon and hydrogen, using the same axial form factor for both. The extracted value of the axial mass parameter $m_A = 0.84^{+0.12}_{-0.04} \pm {0.11} \, {\rm GeV}$ is in very good agreement with the model-independent value extracted from MiniBooNE's neutrino data. Going beyond a one-parameter description of the axial form factor, we extract values of the axial form factor in the range of $Q^2=0.1...1.0$ GeV$^2$, finding a very good agreement with the analogous extraction from the neutrino data. We discuss the implications of these results., 13 pages, 3 figures

We present a pedagogical introduction to NRQED (non-relativistic quantum electrodynamics). NRQED is an effective field theory that describes the interaction of non-relativistic, possibly composite, spin-half particle with the electromagnetic field. We explain in detail how the NRQED Lagrangian is constructed up to and including order $1/M^2$, where $M$ is the mass of the spin-half particle. As a sample application, we derive the Thomson scattering cross section for the low energy scattering of a photon and a possibly composite spin-half particle., Comment: 10 pages

We combine constraints from analyticity with experimental electron-proton scattering data to determine the proton magnetic radius without model-dependent assumptions on the shape of the form factor. We also study the impact of including electron-neutron scattering data, and $\pi\pi\to N\bar{N}$ data. Using representative datasets we find for a cut of $Q^2\leq0.5$ GeV$^2$, $r_M^p=0.91^{+0.03}_{-0.06}\pm0.02$ fm using just proton scattering data; $r_M^p=0.87^{+0.04}_{-0.05}\pm0.01$ fm adding neutron data; and $r_M^p=0.87^{+0.02}_{-0.02}$ fm adding $\pi\pi$ data. We also extract the neutron magnetic radius from these data sets obtaining $r_M^n=0.89^{+0.03}_{-0.03}$ fm from the combined proton, neutron, and $\pi\pi$ data., Comment: 21 pages, 2 figures

Recently, the charge radius of the proton was extracted for the first time from muonic hydrogen. The value obtained is five standard deviations away from similar measurements of regular hydrogen. This talk discusses work done in collaboration with Richard J. Hill, to address this discrepancy. First, we have studied the extraction of the charge radius of the proton from electron-proton scattering data in a model-independent way. We have shown that previous extractions, spanning a period of over 40 years, have underestimated their errors. Second, we have looked at a model-independent analysis of proton structure effects for hydrogen-like bound states, using the tool of an effective field theory, namely NRQED. We have identified hidden model-dependent assumptions in the theoretical calculation behind the muonic hydrogen result., Proceedings of DPF2011, Meeting of the Division of Particles and Fields of the American Physical Society, Brown University, Providence, Rhode Island, USA, August 8-13, 2011 and Proceedings of PANIC 2011, 19th Particles & Nuclei International Conference, MIT, Cambridge, Massachusetts, USA, July 24-29 2011, and eConf C110809 (2012)

Quasielastic neutrino-nucleon scattering is a basic signal process for neutrino oscillation studies. At accelerator energies, the corresponding cross section is subject to significant uncertainty due to the poorly constrained axial-vector form factor of the nucleon. A model-independent description of the axial-vector form factor is presented. Data from the MiniBooNE experiment for quasielastic neutrino scattering on carbon are analyzed under the assumption of a definite nuclear model. The value of the axial mass parameter, m_A=0.85^{+0.22}_{-0.07} +/- 0.09 GeV, is found to differ significantly from extractions based on traditional form factor models. Implications for future neutrino scattering and pion electroproduction measurements are discussed., Comment: 19 pages, 4 figures. v2: figure 3 added, journal version

Proton structure effects in hydrogenic bound states are analyzed using nonrelativistic QED effective field theory. Implications for the Lamb shift in muonic hydrogen are discussed. Model-dependent assumptions in previous analyses are isolated, and sensitivity to poorly constrained hadronic structure in the two-photon exchange contribution is identified., Comment: 5 pages, 1 figure. v2: PRL version

Constraints from analyticity are combined with experimental electron-proton scattering data to determine the proton charge radius. In contrast to previous determinations, we provide a systematic procedure for analyzing arbitrary data without model-dependent assumptions on the form factor shape. We also investigate the impact of including electron-neutron scattering data, and $\pi\pi\to N\bar{N}$ data. Using representative datasets we find r_E^p=0.870 +/- 0.023 +/- 0.012 fm using just proton scattering data; r_E^p=0.880^{+0.017}_{-0.020} +/- 0.007 fm adding neutron data; and r_E^p=0.871 +/- 0.009 +/- 0.002 +/- 0.002 fm adding $\pi\pi$ data. The analysis can be readily extended to other nucleon form factors and derived observables., Comment: 17 pages, 4 figures. v2: references added, minor typos corrected, version to appear in PRD

Using methods from soft-collinear and heavy-quark effective theory, a systematic factorization analysis is performed for the $\bar B\to X_s\gamma$ photon spectrum in the endpoint region $m_b-2E_\gamma={\cal O}(\Lambda_{\rm QCD})$. It is proposed that, to all orders in $1/m_b$, the spectrum obeys a novel factorization formula, which besides terms with the structure $H\,J\otimes S$ familiar from inclusive $\bar B\to X_u l\,\bar\nu$ decay distributions contains "resolved photon" contributions of the form $H\,J\otimes S\otimes\bar J$ and $H\,J\otimes S\otimes\bar J\otimes\bar J$. Here $S$ and $\bar J$ are new soft and jet functions, whose form is derived. These contributions arise whenever the photon couples to light partons instead of coupling directly to the effective weak interaction. The new contributions appear first at order $1/m_b$ and are related to operators other than $Q_{7\gamma}$ in the effective weak Hamiltonian. They give rise to non-vanishing $1/m_b$ corrections to the total decay rate, which cannot be described using a local operator product expansion. A systematic analysis of these effects is performed at tree level in hard and hard-collinear interactions. The resulting uncertainty on the decay rate defined with a cut $E_\gamma>1.6$ GeV is estimated to be approximately $\pm 5%$. It could be reduced by an improved measurement of the isospin asymmetry $\Delta_{0-}$ to the level of $\pm 4%$. We see no possibility to reduce this uncertainty further using reliable theoretical methods., Comment: 63 pages, 11 Figures, Journal Version

We propose a scenario in which the supersymmetry breaking effect mediated by an additional U(1)' is comparable with that of anomaly mediation. We argue that such a scenario can be naturally realized in a large class of models. Combining anomaly with Z' mediation allows us to solve the tachyonic slepton problem of the former and avoid significant fine tuning in the latter. We focus on an NMSSM-like scenario where U(1)' gauge invariance is used to forbid a tree-level mu term, and present concrete models, which admit successful dynamical electroweak symmetry breaking. Gaugino masses are somewhat lighter than the scalar masses, and the third generation squarks are lighter than the first two. In the specific class of models under consideration, the gluino is light since it only receives a contribution from 2-loop anomaly mediation, and it decays dominantly into third generation quarks. Gluino production leads to distinct LHC signals and prospects of early discovery. In addition, there is a relatively light Z', with mass in the range of several TeV. Discovering and studying its properties can reveal important clues about the underlying model., Minor changes: references added, typos corrected, journal version

Combining anomaly with Z' mediation allows us to solve the tachyonic slepton problem of the former and avoid fine tuning in the latter. We describe how the two mechanisms can be combined, and some of the phenomenology of such a joint scenario., Comment: Talk given at the 17th International Conference On Supersymmetry And The Unification Of Fundamental Interactions (SUSY 09), 5-10 Jun 2009, Boston, Massachusetts, USA

In a recent paper, we proposed the possibility that supersymmetry breaking is communicated dominantly via a U(1)' vector multiplet. We also required that the U(1)' plays a crucial role in solving the mu problem. We discuss here in detail both the construction and the phenomenology of one class of such models. The low energy spectrum generically contains heavy sfermions, Higgsinos and exotics ~10-100 TeV; an intermediate M_Z' ~ 3-30 TeV; light gauginos ~100-1000 GeV, of which the lightest can be wino-like; a light Higgs with a mass of ~140 GeV; and a singlino which can be very light. We present a set of possible consistent charge choices. Several benchmark models are used to demonstrate characteristic phenomenological features. Special attention is devoted to interesting LHC signatures such as gluino decay and the decay patterns of the electroweak-inos. Implications for neutrino masses, exotic decays, R-parity, gauge unification, and the gravitino mass are briefly discussed., Comment: Version published in PRD

We address two closely related problems associated with the singlet scalars' potential that are often present in supersymmetric U(1)' models, especially those which maintain the gauge unification of the MSSM in a simple way. The first is the possibility of an accidental global symmetry which results in a light Goldstone boson. The second is the problem of generating a vacuum expectation value for more than one field without reintroducing the $\mu$ problem. We give sufficient conditions for addressing both issues and provide a concrete example to generate them., Comment: 10 pages

We present a new observable sensitive to a certain combination of CP violating phases in supersymmetric extensions of the Standard Model, viz. a triple product of momenta in the cascade decay of a heavy squark via an on-shell neutralino and off-shell slepton. We investigate the regions of parameter space in which the signal is strong enough to be detectable at the LHC with $\sim \bigl(10^2-10^3\bigr)/\sin^2(2\Delta\phi)$ identified events, where $\Delta\phi$ is a certain combination of phases in the MSSM presented in the text., Comment: Several references added

We consider a class of models in which supersymmetry breaking is communicated dominantly via a U'(1) gauge interaction, which also helps solve the \mu problem. Such models can emerge naturally in top-down constructions and are a version of split supersymmetry. The spectrum contains heavy sfermions, Higgsinos, exotics, and Z' ~ 10-100 TeV; light gauginos ~ 100-1000 GeV; a light Higgs ~ 140 GeV; and a light singlino. A specific set of U'(1) charges and exotics is analyzed, and we present five benchmark models. Implications for the gluino lifetime, cold dark matter, and the gravitino and neutrino masses are discussed., Comment: Minor modifications to text to comply by PRL standards

We analyze flavor constraints in the littlest Higgs model with T-parity. In particular, we focus on neutral meson mixing in the K, B, and D systems due to one loop contributions from T-parity odd fermions and gauge bosons. We calculate the short distance contributions to mixing for a general choice of T-odd fermion Yukawa couplings. We find that for a generic choice of textures, a TeV scale GIM suppression is necessary to avoid large contributions. If order one mixing angles are allowed in the extended flavor structure, the mass spectrum is severely constrained, and must be degenerate at the 1-5% level. However, there are still regions of parameter space where only a loose degeneracy is necessary to avoid constraints. We also consider the B(s) system, and identify a scenario in which the mixing can be significantly enhanced beyond the standard model prediction while still satisfying bounds on the other mixing observables. We present both analytical and numerical results as functions of the T-odd fermion mass eigenvalues., Comment: 29 pages, 7 figures

A shape-function independent relation is derived between the partial B->X_u+l+nu decay rate with a cut on P_+=E_X-P_XX_s+gamma photon-energy spectrum. The leading-power contribution to the weight function is calculated at next-to-next-to-leading order in renormalization-group improved perturbation theory, including exact two-loop matching corrections at the scale mu_i^2 ~ m_b*Lambda_{QCD}. The overall normalization of the weight function is obtained up to yet unknown corrections of order [alpha_s(m_b)]^2. Power corrections from phase-space factors are included exactly, while the remaining subleading contributions are included at first order in 1/m_b. At this level unavoidable hadronic uncertainties enter, which are estimated in a conservative way. The combined theoretical accuracy in the extraction of |V_{ub}| is at the level of 5% if a value of Delta near the charm threshold can be achieved experimentally., Comment: 22 pages, 4 figures; few comments and one reference added; version to appear in JHEP

The contributions of subleading shape functions to inclusive decay distributions of B mesons are derived from a systematic two-step matching of QCD current correlators onto soft-collinear and heavy-quark effective theory. At tree-level, the results can be expressed in terms of forward matrix elements of bi-local light-cone operators. Four-quark operators, which arise at O(g^2), are included. Their effects can be absorbed entirely into a redefinition of other shape functions. Our results are in disagreement with some previous studies of subleading shape-function effects in the literature. A numerical analysis of B->X_u+l+nu decay distributions suggests that power corrections are small, with the possible exception of the endpoint region of the charged-lepton energy spectrum., 22 pages, 2 figures; several typos corrected; version published in JHEP

Using methods of effective field theory, factorized expressions for arbitrary B -> X_u l nu decay distributions in the shape-function region of large hadronic energy and moderate hadronic invariant mass are derived. Large logarithms are resummed at next-to-leading order in renormalization-group improved perturbation theory. The operator product expansion is employed to relate moments of the renormalized shape function with HQET parameters such as m_b, Lambda(bar) and lambda_1 defined in a new physical subtraction scheme. An analytic expression for the asymptotic behavior of the shape function is obtained, which reveals that it is not positive definite. Explicit expressions are presented for the charged-lepton energy spectrum, the hadronic invariant mass distribution, and the spectrum in the hadronic light-cone momentum P_+ = E_H - P_H. A new method for a precision measurement of |V_{ub}| is proposed, which combines good theoretical control with high efficiency and a powerful discrimination against charm background., 51 pages, 10 figures; minor corrections, version to appear in Nuclear Physics B

The contribution of subleading jet functions to inclusive decay distributions of $B$ mesons are derived from a systematic two-step matching of QCD current correlators onto soft collinear and heavy quark effective theory. Focusing on the tree level matching of QCD onto soft collinear effective theory, the subleading jet functions are defined to all orders in $\alpha_s(\mu_i)$ (with $\mu_i^2\sim m_b\Lambda_{\rm QCD}$) and are calculated explicitly at first order in $\alpha_s(\mu_i)$. We present explicit expressions for the decay rates of $B\to X_u l \bar\nu$ and the $Q_{7\gamma}-Q_{7\gamma}$ contribution to $B\to X_s \gamma$, where the subleading jet functions are multiplied by a tree level hard function and appear in a convolution with the leading order shape function. Together with the recent two loop calculation of the leading order hard function for $B\to X_u l \bar\nu$, this paper will allow for a more precise description of inclusive B decays in the end point region., Comment: Minor changes: reference added, typos corrected, journal version