Recent results of searches for events containing isolated leptons and missing transverse momentum at HERA are presented. Searches in this final state have yielded notable excesses over Standard Model expectations in the past. Searches for isolated leptons in channels corresponding to all three generations of leptons over the full HERA running period are now available. The combined H1+ZEUS results for searches for electrons and muons are compatible with the Standard Model.
Recent results from the H1 and ZEUS experiments are reported on electroweak physics and on searches for new physics. All results are in good agreement with the Standard Model.
Searches for contact interactions, leptoquark bosons and excited fermions carried out at the HERA ep collider are presented here. The searches are based on ~ 40 pb^-1 of e+ p data per experiment collected at a centre of mass energy ~ 300 GeV. First results on e- p data collected in 1998-1999 are also presented.
Isolated hard photons have been measured with jets in Deep Inelastic Scattering using the ZEUS detector at HERA. Preliminary results for the cross sections are presented.
Recent results on searches for new physics at Run II of the Tevatron and highlights from HERA are reported. The searches cover many different final states and a wide range of models. All analyses have at this point led to negative results, but some interesting anomalies have been found.
The HERA collaborations, H1 and ZEUS, have searched for physics beyond the Standard Model in ep collisions at centre-of-mass energies of up to 319 GeV. In this article the experimental results coming from the HERA I phase are summarised and the constraints on theories of new physics including Contact Interactions, Large Extra Dimensions, Leptoquarks, FCNC and various scenarios in R-parity violating supersymmetry are discussed. In addition the first results on searches for new physics coming from the upgraded HERA II collider are presented.
The H1 and ZEUS collaborations have used the HERA I data to search for physics beyond the SM and to test electroweak physics in electron-proton collisions. The new period of data taking (HERA II) has started and first HERA II analyses become available. An overview is given of recent highlights, including isolated lepton and multi-lepton events, tests of models of new physics and the first systematic search for deviations in all final states with high transverse momentum.
Searches for physics beyond the Standard Model are reported from electron-proton collisions at a center of mass energy of 318 GeV. Results on a completely model independent search for deviations from Standard Model predictions at large transverse momenta are reported as well as generic searches for contact interactions, leptoquarks and excited fermions from the H1 and ZEUS experiments.
Signals of physics beyond the Standard Model at HERA have been searched for by the H1 and ZEUS collaborations. Results are reported about searches of contact interaction effects, leptoquarks, R-parity violating squarks, excited fermions and single top production. The analyses used the data set collected during the HERA phase I, consisting in about 110 (15) pb^{-1} of e^+p (e^-p) collisions per experiment. No evidence for new physics has been found and limits have been set on the parameters of the models considered.
Searches for R-parity violating supersymmetry performed at the H1 experiment are presented. Emphasis is put on searches for squarks, which may be resonantly produced at the HERA $ep$ collider in supersymmetry where R-parity is violated. The preliminary results presented here were obtained using data collected at a centre-of-mass energy of 320 GeV and corresponding to an integrated luminosity of 63 pb$^{-1}$.
At HERA, new physics processes beyond the SM are probed in e^+/- proton collisions at a center of mass energy of 300-318 GeV. Recent results on searches obtained by the H1 and ZEUS experiments are presented with an emphasis on data taken in e^-p collisions in the years 1998/99 and in e^+p collisions in the years 1999 and 2000.
The high energy programme of the HERA collider ended in March 2007. During the whole HERA programme, a combined total integrated luminosity of 1 fb$^{-1}$ was collected by the H1 and ZEUS experiments. In this context, an overview of the most recent results of both experiments concerning searches for new physics is presented. The topics covered are searches for contact interactions, leptoquarks and excited leptons, as well as studies of the isolated lepton and multi-lepton topologies, and a general signature based search.
Various searches for leptoquarks, scalar quarks in $R_p$-violating supersymmetric models, and excited fermions performed by the HERA experiments H1 and ZEUS are reviewed. No evidence for new particle production was observed from data collected by both experiments since 1994 in either electron-proton and positron-proton collisions. Stringent limits derived on the masses and couplings of these new particles are compared whenever appropriate with those from LEP, the Tevatron and low energy experiments.
The high energy program of the HERA $ep$ collider ended in March 2007, where data equivalent to an integrated luminosity of $\sim$ 0.5 fb$^{-1}$ has been collected by the H1 experiment. In this context, some of the most recent results from H1 about searches for new phenomena are presented.
A search for events with one or more isolated leptons in the final state is performed on a data sample collected in e+-p collisions with the H1 and ZEUS detectors at the HERA collider. The data sample corresponds to an integrated luminosity of ~1 fb-1, representing the full HERA high-energy data set. The yields of single, di- and tri-lepton events are measured and compared to the Standard Model predictions, looking for possible deviations. No significant discrepancy with respect to the Standard Model expectations is observed.
Searches for physics beyond the Standard Model have been performed in high-energy $e^{\pm}p$ collisions at HERA. No significant deviation from the Standard Model has been observed while searching for contact interactions, extra dimensions, leptoquarks, R-parity violating squarks and excited fermions. Exclusion limits have been inferred which extend or complement bounds from other colliders. The H1 collaboration has observed a puzzling excess of events with an high $P_t$ isolated lepton and missing transverse momentum, and interpretation as flavour changing neutral currents has been explored.
Recent results on searches for new particles at the electron-proton collider HERA are reported. Based on roughly 100pb-1 of e^+p data and 16pb-1 of e^-p data per experiment, taken in the years 1994-2000, the H1 and ZEUS collaborations have derived new exclusion limits for the direct production of excited fermion states and leptoquarks. The latter are searched for in different decay channels, including lepton-flavor violating decays. The production of R_P-violating squarks followed by leptoquark-like decays to lepton and quark is studied, as are cascade decays yielding multi-jet plus lepton sig…
A search for events with an isolated high-energy lepton and large missing transverse momentum has been performed with the ZEUS detector at HERA using a total integrated luminosity of 504 $\mathrm{pb}^{-1}$. The results agree well with Standard Model predictions. The cross section for production of single $W$ bosons in electron-proton collisions with unpolarised electrons is measured to be $0.89^{+0.25}_{-0.22}$ (stat.) $\pm{0.10}$ (syst.) pb.
The latest results from the H1 and ZEUS collaborations are presented on rare Standard Model processes and searches for physics Beyond the Standard Model. Intriguing events containing high transverse momentum leptons are observed by H1 and many competitive limits are set by both collaborations on the production of new particles in a variety of supersymmetry scenarios.
Events with isolated leptons and missing transverse momentum are searched for in electron- or positron-proton collisions at HERA by the H1 and ZEUS experiments. Such events may be explained within the Standard Model by W boson production, followed by leptonic decay. The analysis performed including HERA I and the recently collected data at HERA II results in clear evidence of W production. However, H1 collaboration observes an excess of events in e^+p collisions, not supported so far by ZEUS. If the difference between the H1 and ZEUS observations is attributed to a statistical fluctuation, the…
The H1 and ZEUS collaborations at HERA have searched for signatures of physics beyond the Standard Model with high Q^2 neutral current deep inelastic electron-proton and positron-proton scattering events. No significant deviations from Standard Model predictions were observed. Various eeqq contact nteraction models have been considered. Limits on the compositeness scale in general eeqq contact interaction models, mass to the Yukawa coupling ratio for heavy leptoquarks, the effective Planck mass scale in models with large extra dimensions and the effective quark charge radius are presented.
Recent results on searches for physics beyond the Standard Model obtained by the H1 and ZEUS experiments are reported here. After a brief introduction to the HERA collider, indirect searches for contact interactions and extra-dimensions are presented as well as direct searches for new physics including leptoquarks, lepton-flavour violation, squarks produced by R-parity violation and excited fermions. New results from isolated lepton events and single top searches are also presented. Finally the future prospects of HERA-2 are shown.
Results of a general search for new phenomena at high transverse momentum and of a dedicated search for events with isolated leptons and missing transverse momentum are reported. These searches were performed on a data sample collected at HERA in e+-p collisions with the H1 detector in the period 1994-2004. The results obtained in the isolated lepton search are compared with those obtained by the ZEUS collaboration in the period 1994-2000 and limits on the anomalous FCNC production of single top events are presented.
The photoproduction of isolated photons, both inclusive and together with a jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of $374\, \mathrm{pb}^{-1}$. Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges $6 < E_T^γ< 15$ GeV and $-0.7 < η^γ< 0.9,$ and for jet transverse-energy and pseudorapidity ranges $4 < E_T^{jet} < 35$ GeV and $-1.5 < η^{jet} < 1.8,$ for exchanged-photon virtualities $Q^2 < 1$ GeV$^2$. Differential cross sections are also presented for inclusive isolated-photon production as funct…
Events with high energy isolated electrons, muons or tau leptons and missing transverse momentum are studied using the full e^\pm p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb^{-1}. Within the Standard Model, events with isolated leptons and missing transverse momentum mainly originate from the production of single W bosons. The total single W boson production cross section is measured as 1.14 \pm 0.25 (stat.) \pm 0.14 (sys.) pb, in agreement with the Standard Model expectation. The data are also used to establish limits on the WWγgau…
The H1 and ZEUS collaborations have searched for signals of physics beyond the Standard Model in ep collisions at a center-of-mass energy of 301-319 GeV. During the HERA I phase each experiment accumulated an integrated luminosity of about 110 pb^{-1} for e^+p and about 15 pb^{-1} for e^-p collisions. The data have been analysed searching for contact interaction effects, leptoquarks, lepton flavor violation, squarks in R-parity violating supersymmetric models, excited fermions and FCNC single top production. In this article a summary of the results is given.
The ZEUS detector at HERA has been used to measure the photoproduction of isolated photons in diffractive events. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 < E_T^gamma < 15 Gev and -0.7 < eta^gamma < 0.9, inclusively and with a jet with transverse-energy an pseudorapidity in the ranges 4 < ETjet < 35 GeV and -1.5 < etajet < 1.8, for an integrated luminosity of 374 pb^{-1}. Further kinematic variables studied include the fractions of the incoming photon energy and of the colourless exchange ("Pomeron") energy that are imparted to a photon-jet final…
Searches for narrow baryonic states in the K0s-p, K+p, Xi-pi and bar{X}+pi decay channels are reported. The data were collected with the ZEUS detector at HERA using an integrated luminosity of 121 pb-1. The searches were performed in the central rapidity region of inclusive deep inelastic scattering at an $ep$ centre-of-mass energy of 300--318 GeV for exchanged photon virtuality, Q2, above 1 GeV2. The results support the existence of a narrow baryonic state with strangeness in K0s-p and K0s-\bar{p} decay channels, consistent with the pentaquark prediction. No pentaquark signals were found in t…
Recent results from searches for new physics at HERA are reviewed. Exploiting the uniqueness of lepton-hadron collisions at high energy, searches are performed for electron-quark resonant states (leptoquarks or squarks in R-parity-violating supersymmetry) or excited states of fermions. New phenomena at a very high energy scale, manifested at present energies as effective four-fermion contact interaction, are also investigated, including cases with lepton-flavor violation. Finally, the status of events with a high-energy lepton and missing transverse momentum is presented, resulting in the most…
HERA is the only high energy electron-proton collider in the world today and hence has unique opportunities both to probe the structure of the proton and to search for physics beyond the Standard Model. Results are presented for measurements of both neutral and charged current cross sections, and for searches for exotic processes involving direct electron-quark interactions (leptoquarks and R-parity violating SUSY), generic coupling models (contact interactions) and exclusive final states (isolated leptons and missing PT, single top production and pentaquarks). Exclusion limits on proposed mod…
Recent results from searches for physics beyond the Standard Model (SM) in electron/positron-proton collisions at HERA at center-of-mass energies of 300 and 320 GeV are presented. They were performed on a data sample collected in the period 1994-2004 by the H1 and ZEUS collaborations. The data have been analysed searching for leptoquarks, light gravitinos in R-parity violating supersymmetric models and magnetic monopoles. Results of a general search for new phenomena at high transverse momentum and of a dedicated search for events with isolated leptons and missing transverse momentum are also …
The analysis of events with isolated leptons and missing transverse momentum in the H1 experiment is discussed for the electron, muon and tau channels. In the Standard Model (SM) framework, production of real W-bosons gives rise to such topologies. Contributions to the background are dominated by QCD processes. An excess of observed signal over background presents a chance of the discovery of new physics. The results using the HERA 1994-2006 data set corresponding to 341 pb^-1 are presented. While the e- p sample shows good agreement between data and SM expectation, in e+ p collisions an exces…
A search for events with an imbalance in transverse momentum and with isolated high energy leptons has been carried out at the positron-proton collider HERA. One event with an e^- and five events with a mu^+- are found together with evidence for undetected particles carrying transverse momentum. Within the Standard Model the dominant origin of events with this kind of topology is the production of W bosons with subsequent leptonic decay. Three of the six events are within measurement errors found in a region of phase space likely to be populated by this process, while the remaining events show…
The search for events containing isolated leptons (electrons or muons) and missing transverse momentum produced in e^{\pm}p collisions is performed individually and in a common phase space with the H1 and ZEUS detectors at HERA in the period 1994--2007. The analysed H1+ZEUS data sample corresponds to an integrated luminosity of 0.97 fb^{-1}, and composes of the complete high energy data from the HERA programme. A total of 87 events are observed in the data, compared to a Standard Model (SM) prediction of 92.7 \pm 11.2. At large hadronic transverse momentum P_{T}^{X} > 25 GeV in the e^{+}p data…
Recent results from H1, ZEUS, HERMES and HERA-B on searches for exotic baryons in ep collisions, eD scattering and pA scattering at HERA are reviewed. Evidence for the production of the strange pentaquark Theta^+ and of a narrow anti-charmed baryon decaying to D^{*-}p together with negative results of pentaquark searches at HERA are presented.
Searches in ep collisions for heavy excited fermions have been performed with the ZEUS detector at HERA. Excited states of electrons and quarks have been searched for in e^+p collisions at a centre-of-mass energy of 300 GeV using an integrated luminosity of 47.7 pb^-1. Excited electrons have been sought via the decays e*->egamma, e*->eZ and e*->nuW. Excited quarks have been sought via the decays q*->qgamma and q*->qW. A search for excited neutrinos decaying via nu*->nugamma, nu*->nuZ and nu*->eW is presented using e^-p collisions at 318 GeV centre-of-mass energy, corresponding to an integrated…
Recent results from H1 and ZEUS on searches for exotic baryons in $ep$ collisions at HERA are reviewed. Evidence for the production of the strange pentaquark $Θ^+$ and of a narrow anti-charmed baryon decaying to $D^{*-} p$ together with negative results of pentaquark searches at HERA are presented.
An overview of experimental results on searches for new phenomena at HERA is presented. The complementarity with searches performed at other experiments is discussed and the prospects for a discovery, using the full HERA data to be delivered until mid-2007, are presented.
Searches for Physics beyond the Standard Model have entered an exciting new phase: the complete HERA data samples obtained until the end of operations in the Summer of 2007 are now available for analysis. ZEUS and H1 have each collected about 0.5 fb^{-1} of lepton proton data, distributed over electron and positron running, and over different lepton beam polarisations. At the same time the Fermilab Tevatron proton-antiproton collider is accumulating data at unprecedented rates, with current analyses based on up to 3 fb^{-1}. The Tevatron experiments DZERO and CDF have each already recorded ove…
Events containing an isolated prompt photon with high transverse energy, together with a balancing jet, have been observed for the first time in photoproduction at HERA.The data were taken with the ZEUS detector, in a $γp$ centre of mass energy range 120--250 GeV. The fraction of the incoming photon energy participating in the production of the prompt photon and the jet, $x_γ$, shows a strong peak near unity, consistent with LO QCD Monte Carlo predictions. In the transverse energy and pseudorapidity range $5\le \eTg < 10$ GeV, $-0.7 \le η^γ< 0.8$, $\eTj\ge 5$ GeV, and $-1.5\le η^{jet}\le 1.8$,…
The production of isolated photons in deep-inelastic scattering $ep\to e γX$ is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared $4<Q^2<150 $~GeV$^2$ and a mass of the hadronic system $W_X>50$ GeV. The analysis is based on a total integrated luminosity of 227~pb$^{-1}$. The production cross section of isolatedphotons with a transverse energy in the range $3 < E_T^γ< 10$ GeV and pseudorapidity range $-1.2 < η^γ< 1.8$ is measured as a function of $E_T^γ$, $η^γ$ and $Q^2$. Isolated photon cross sections are also …
Recent results from searches for physics beyond the Standard Model (SM) in $e^\pm$-proton collisions at a center of mass energy of 300 -- 318 GeV at HERA are presented. Searches for excitations of fermions and for the production of squarks in R-parity-violating Supersymmetry (SUSY) are reviewed.
Inclusive production of K0S K0S in ep collisions was studied with the ZEUS detector. Significant production of JPC=2++ tensor mesons and of the 0++ glueball candidate f0(1710) was seen. Masses and widths were compared with previous experiments. The H1 Collaboration saw a charm pentaquark candidate in the D*p spectrum at 3.1 GeV, which was not confirmed by a ZEUS higher statistics search. With the full HERA data, H1 did not see a signal in this region. Masses, widths and helicity parameters of excited charm and charm-strange mesons were measured by ZEUS. Rates of c-quarks hadronising into these…
Recent spectroscopy studies performed in high energy ep collisions by the H1 and ZEUS Collaborations are described. The status of the searches for the strange pentaquark, the Theta+, is presented as well as results on searches for further exotic states such as the Sigma--. The evidence for the observation of a pentaquark state containing the charmed quark, the Theta_c, is discussed and the result is given on searches for glueball candidates at HERA.
The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges $5 < E_T < 15$ GeV and $-0.7 < η< 0.9,$ inclusively and also with a jet with transverse energy and pseudorapidity in the ranges $4 < E_{jet} < 35$ GeV and $-1.5 < η_{jet} < 1.8,$ using a total integrated electron-proton luminosity of 456 pb$^{-1}$. A number of kinematic variables were studied and compared to predictions from the Rapgap Monte Carlo model. An excess of data is observed above t…
A search for events containing isolated tau leptons and large missing transverse momentum, not originating from the tau decay, has been performed with the ZEUS detector at the electron-proton collider HERA, using 130 pb^-1 of integrated luminosity. A search was made for isolated tracks coming from hadronic tau decays. Observables based on the internal jet structure were exploited to discriminate between tau decays and quark- or gluon-induced jets. Three tau candidates were found, while 0.40 +0.12 -0.13 were expected from Standard Model processes, such as charged current deep inelastic scatteri…
A search for events containing an isolated electron or muon and missing transverse momentum produced in ep collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb^-1. The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e+p data, at large hadronic transverse momentum PtX >25 GeV, a total of 23 events are observed compared to a prediction of 14.0 \pm 1.9. The total single W boson production cross sectio…
The search for events containing isolated leptons (electrons or muons) and missing transverse momentum produced in $e^{\pm}p$ collisions is performed with the H1 detector at HERA in the period 1994--2005. The analysed data sample corresponds to an integrated luminosity of 279 pb$^{-1}$, which includes 53 pb$^{-1}$ of $e^{+}p$ data and 107 pb$^{-1}$ of $e^{-}p$ data from the new HERA~II phase. A total of 40 events are observed in the data, compared to a Standard Model (SM) prediction of 34.3 $\pm$ 4.8. At large hadronic transverse momentum $P_{T}^{X} >$ 25 GeV, a total of 17 events are observed…
The latest results from the H1 and ZEUS collaborations are presented on leptoquark production and rare Standard Model processes. The data were taken in the period 1994-2005, at a centre of mass energy of up to 319 GeV. Intriguing events containing isolated leptons and missing transverse momentum, as well as multi-lepton events, are observed by H1 in regions of phase space where the SM prediction is low. Interpretations of the observed excesses in terms of physics Beyond the Standard Model are also discussed.
Recent results on searches for signals of physics beyond Standard Model at the ep collider HERA are reviewed. Limits obtained for contact interaction models, large extra dimensions and finite quark radius are presented. Searches for excited-fermion resonances yield unique limits on excited electrons and neutrinos. Finally, measurement of W production cross section in ep collision is presented.
The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon-proton transverse-energy and pseudorapidity ranges 5<ET(gamma)<15 GeV and -0.7<eta(gamma)<0.9 inclusively and also with a jet with transverse energy and pseudorapidity in the range 4<ET(jet)<35 GeV and -1.5<eta(jet)<1.8, using a total integrated electron-proton luminosity of 374 pb-1. A number of kinematic variables were studied and compared to predictions from the RAPGAP Monte Carlo model. An excess of data is observed above the RAPG…
Measurements of the production of events containing isolated high energy leptons (electrons and muons) produced in ep collisions have been performed with the H1 and ZEUS detectors at HERA, using data collected in the period 1994-2007. Topologies with more than one charged lepton or with a charged lepton in coincidence with missing transverse momentum are analysed. The H1 and ZEUS data, corresponding to an integrated luminosity of about 0.5 fb^-1 per experiment, are combined in a common phase space. The observed event yields are compared to the predictions from the Standard Model. In general a …
Recent results of searches for new physics at HERA using the complete data sample corresponding to about 0.5/fb per experiment are reviewed. Searches for leptoquarks, isolated leptons (electrons, muons and taus) and a generic search for new physics in many topologies are reported. No evidence for new physics is found. The ep collisions at HERA are ideally suited to search for resonantly produced squarks in SUSY with R-parity violation. It is highlighted how the present results can be interpreted in this way.
The K0s-p invariant mass spectrum was reconstructed in several kinematic regions with the main emphasis on the studies of the production mechanism of the Theta+ candidate recently observed by ZEUS. The candidate Theta+ signal was found to be produced predominantly in the forward hemisphere in the laboratory frame. This is unlike the case for the Lambda(1520) or the Lambda(c), and indicates that the Theta+ may have an unusual production mechanism related to proton-remnant fragmentation. H1 does not observe a signal and sets an upper limit at 95% C.L. which does not exclude the ZEUS observation.
A search for events with a high energy isolated electron or muon and missing transverse momentum has been performed at the electron-proton collider HERA using an integrated luminosity of 13.6 pb-1 in e-p scattering and 104.7 pb-1 in e+p scattering. Within the Standard Model such events are expected to be mainly due to W boson production with subsequent leptonic decay. In e-p interactions one event is observed in the electron channel and none in the muon channel, consistent with the expectation of the Standard Model. In the e+p data a total of 18 events are seen in the electron and muon channel…
Preliminary H1 results on dedicated searches for QCD instanton induced processes in DIS are presented. The investigations are based on the expected characteristics of their hadronic final state. Searches were performed in the kinematical region x > 0.001, 0.1 < y < 0.6 and the polar angle of scattered positron greater than 156 degrees.
A search for squarks in R-parity violating supersymmetry is performed in e^+p collisions at HERA at a centre of mass energy of 300 GeV, using H1 data corresponding to an integrated luminosity of 37 pb^(-1). The direct production of single squarks of any generation in positron-quark fusion via a Yukawa coupling lambda' is considered, taking into account R-parity violating and conserving decays of the squarks. No significant deviation from the Standard Model expectation is found. The results are interpreted in terms of constraints within the Minimal Supersymmetric Standard Model (MSSM), the cons…
A search for the leptonic decays of W bosons produced in the reaction e^+ p\to e^+ W^\pm X at a centre-of-mass energy of 300 GeV has been performed with the ZEUS detector at HERA using an integrated luminosity of 47.7 pb^-1 . Three events consistent with W\to eνdecay are found, giving a cross section of 0.9 +1.0 -0.7 \pm 0.2 pb, in good agreement with the Standard Model prediction. The corresponding 95% C.L. upper limit on the cross section is 3.3 pb. A search for the decay W\to μνhas a smaller selection efficiency and yields no candidate events. Limits on the cross section for W production wi…
Searches for excited electrons and neutrinos have been performed using the complete HERA I and II data samples collected by the H1 detector at $\sqrt{s}=320$ GeV corresponding to an integrated luminosity of up to 435 pb$^{-1}$. In absence of a signal, the limits on the ratio of the coupling to the compositeness scale derived extend the excluded region to higher masses than has been possible in previous searches.
Recent results from HERA are presented. The main reviewed subjects are polarized DIS cross sections, parton density determination, diffractive PDFs, multi-jet production and searches for physics beyond the Standard Model.
Recent results for direct searches for physics beyond the Standard Model are reviewed. The results include Tevatron II data up to 1.2 fb-1 and HERA results up to 350 pb-1. Searches for Supersymmetry, for compositeness and for large extra dimensions are presented. The excess of events with an isolated lepton and high missing transverse momentum at HERA is discussed.
